. . . this is not in a zoo - it is wildlife! One hit with their giant claws and you are damaged! Luckily they are not aggressive . . .

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The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

Amid the brightly coloured non-figurative windows on the northern side of Saint George's Presbyterian Church stands one figurative window. Dedicated to American John Kane Smyth, the window was made by Melbourne stained glass manufacturer Ferguson and Urie. Although there is no date on the window, I believe it was created in the 1890s. The window represents two scenes in the life of Jesus: The Settlement about the Tribute Money, and The Interview with the Rich Young Ruler. The right-hand pane is the Interview with the Rich Young Ruler window from the Book of Luke. A certain ruler asks Jesus, "Good teacher, what must I do to inherit eternal life?" As part of his reply Jesus says, "How hard it is for the rich to enter the kingdom of God! Indeed, it is easier for a camel to go through the eye of a needle than for a rich man to enter the kingdom of God", after telling the ruler that he should sell all he has and follow him for a guarantee to eternal life. Jesus stands with his hand raised, whilst the ruler in richly patterned robes and a fine turban stands beside him. Two apostles stand behind them, their faces just visible. The window contains a Biblical quote from the Book of Mark XII - 17 in the bottom dedication panel: "Render to Caesar the things that are Caesar's, and to God the things that are God's".

John Kane Smyth was the Vice-Consul for the United States of America in Melbourne, and he was just one of a number of wealthy Americans who attended services at Saint George's Presbyterian Church. In his honour the top round ventilator window has the American Stars and Stripes in it. Interestingly it features the Thirty-Six Stars and Stripes flag which was well outdated by the time this window as installed. The Thirty-Six Stars and Stripes flag became the official United States Flag on July 4th, 1865 after the admission of Nevada into the union. However it was only to last for two years when Nebraska joined the union. John Kane Smyth served on Saint George's Presbyterian Church's Board of Management for many years and is recognised as having given good service in the Saint George's Presbyterian Church's 1876 - 1926 Jubilee Souvenir Book.

The former Saint George's Presbyterian Church was constructed on a plot of land reserved in Chapel Street for the Presbyterian Church of Victoria in 1866. Initially services were held in a small hall whilst fundraising efforts advanced the erection of a church. The architect Albert Purchas was commissioned to design the church and the foundation stone for the western portion of the nave was finally laid in April 1877 by Sir James McCulloch. The first service was held in the church on the 1st of October 1877. The first clergyman of the former Saint George's Presbyterian Church was the Reverend John Laurence Rentoul (father to world renown and much loved Australian children's book illustrator Ida Rentoul Outhwaite). However, the swelling Presbyterian congregation of St Kilda and its surrounding districts quickly outgrew the initial Saint George's Presbyterian Church building, so Albert Purchas was obliged to re-design and enlarge the church to allow a doubling in capacity. Robert S. Ekins was the contractor and his tender was £3000.00. It is this imposing church building, reopened in 1880, that we see today. The "Australasian Sketcher with Pen and Pencil" noted that the total length of the building was 118 feet and 6 inches (36 metres), by 40 foot (12 metres) wide and that the striking octagonal tower to the north-west was 110ft 6 in high. It perhaps reflected better the wealth and aspirations of the congregation.

The former Saint George's Presbyterian Church is constructed on bluestone foundations and is built in an ornate polychromatic Gothic Revival style in the tradition of English designers like William Butterfield and John L. Pearson. Built of red brick building, it is decorated in contrasting cream bricks and Waurn Ponds freestone dressings. It features a slate roof with prominent roof vents, iron ridge cresting and fleche at the intersection of the nave and transepts. The front facade of the church is dominated by the slender, banded octagonal tower topped by a narrow spire. The entrance features a double arched portal portico. The facade also features a dominant triangular epitrochoidal (curved triangular form) rose window. The church, like its bluestone neighbour All Saints Church of England, is built to a T-shaped plan, with an aisleless nave, broad transepts and internal walls of cream brick, relieved with coloured brickwork. The former Saint George's Presbyterian Church was one of the first major church design in Melbourne in which polychrome brickwork was lavishly employed both externally and internally.

The inside of the former Saint George's Presbyterian Church is equally as grand as the exterior, with ornamental Gothic Revival polychromatic brickwork, a lofty vaulted ceiling, deal and kauri pine joinery and pulpit and reredos of Keene's cement. The building originally contained a complete set of Victorian stained glass windows by well known and successful Melbourne manufacturers Ferguson and Urie, all of which remain intact today except for one of the non-figurative windows which was replaced by a memorial window to Samuel Lyons McKenzie, the congregation’s beloved minister, who served from 1930 to 1948, in 1949. The earliest of the Ferguson and Urie windows are non-figurative windows which feature the distinctive diaper pattern and floral motifs of Fergus and Urie's work, and are often argued to be amongst the finest of their non-figurative designs. The large triple window in the chancel was presented by Lady McCulloch in memory of the ‘loved and dead’. Another, in memory of John Kane Smyth, the Vice-Consul for the United States of America in Melbourne, has the American Stars and Stripes on the top ventilator above it. An organ by Thomas C. Lewis of London, one of the leading 19th century English organ builders, was installed in the south transept in 1882. It was designed to blend with its architectural setting, with pipework styled to avoid the obstruction of windows. The action of this organ was altered in 1935, but the pipework, and the original sound, have been retained.

Over the years many spiritual and social activities were instituted at Saint George’s, Presbyterian Church some of short duration such as the Ladies’ Reading Club which operated between 1888 and 1893. There were segregated Bible classes for young men and women, the Presbyterian Women’s Missionary Union, formed in 1892, a cricket club and a floral guild. Guilds teaching physical culture for girls, boys and young men began in 1904. They were entirely financed by John Maclellan and the idea extended to other denominations throughout Victoria. John Maclellan died in 1936 and the guilds ceased at Saint George’s Presbyterian church through lack of funds although in 1977 the members of the girls’ guild were still holding bi-annual reunions and raising money for charity. Sadly, the Presbyterian congregations may have been large in the Nineteenth Century, but by St George's Presbyterian Church's 110th centenary, its doors had already closed during the week due to dwindling numbers and an ageing congregation as a result of the general decline in church attendances after the Second World War exacerbated by the changing nature of St Kilda and the decrease in numbers of residents living in the vicinity of the church. So it stood, forlorn and empty and seemingly nothing more than a relic of a glorious but bygone religious past. However in 1990, Saint Michael's Grammar School across the road leased the Victorian Heritage listed building during weekdays, and it was eventually sold to them in 2015. It now forms part of the school's performing-arts complex, and it has a wonderful new lease of life.

St George's Presbyterian Church is sometimes hired out for performances, and I had the pleasure of receiving an invitation to hear Handel's Messiah performed there in 2009. The ecclesiastical acoustics made the performance all the more magnificent. I remember as I sat on one of the original (hard) kauri pine pews, I looked around me and admired the stained glass and ornamental brickwork. I tried without success over several subsequent years to gain access to the church's interior, settling for photographs of the exterior instead, but it wasn't until 2018 that I was fortunate enough to gain entry to photograph the church's interior. The former St George's Presbyterian Church was opened up to the public for one Sunday morning only as part of Open House Melbourne in July 2018. It was a fantastic morning, and I am very grateful to the staff who manned the church for the day and watched bemused as I photographed the stained glass extensively and in such detail.

Albert Purchas, born in 1825 in Chepstow, Monmouthshire, Wales, was a prominent Nineteenth Century architect who achieved great success for himself in Melbourne. Born to parents Robert Whittlesey Purchas and Marianne Guyon, he migrated to Australia in 1851 to establish himself in the then quickly expanding city of Melbourne, where he set up a small architect's firm in Little Collins Street. He also offered surveying services. His first major building was constructing the mansion "Berkeley Hall" in St Kilda on Princes Street in 1854. The house still exists today. Two years after migrating, Albert designed the layout of the Melbourne General Cemetery in Carlton. It was the first "garden cemetery" in Victoria, and his curvilinear design is still in existence, unaltered, today. In 1854, Albert married Eliza Anne Sawyer (1825 - 1869) in St Kilda. The couple had ten children over their marriage, including a son, Robert, who followed in his father's footsteps as an architect. Albert's brother-in-law, Charles Sawyer joined him in the partnership of Purchas and Sawyer, which existed from 1856 until 1862 in Queens Street. The firm produced more than 140 houses, churches, offices and cemetery buildings including: the nave and transepts of Christ Church St Kilda between 1854 and 1857, "Glenara Homestead"in Bulla in 1857, the Melbourne Savings Bank on the corner of Flinders Lane and Market Street (now demolished) between 1857 and 1858, the Geelong branch of the Bank of Australasia in Malop Street between 1859 and 1860, and Beck's Imperial Hotel in Castlemaine in 1861. When the firm broke up, Albert returned to Little Collins Street, and the best known building he designed during this period was Saint. George's Presbyterian Church in St Kilda East between 1877 and 1880. The church's tall polychomatic brick bell tower is still a local landmark, even in the times of high rise architecture and development, and Saint, George's itself is said to be one of his most striking church designs. Socially, Albert was vice president of the Royal Victorian Institute of Architects for many years, before becoming president in 1887. He was also an inventor and philanthropist. Albert died in 1909 at his home in Kew, a wealthy widower and much loved father.

The stained glass firm of Ferguson and Urie was established by Scots James Ferguson (1818 – 1894), James Urie (1828 – 1890) and John Lamb Lyon (1836 – 1916). They were the first known makers of stained glass in Australia. Until the early 1860s, window glass in Melbourne had been clear or plain coloured, and nearly all was imported, but new churches and elaborate buildings created a demand for pictorial windows. The three Scotsmen set up Ferguson and Urie in 1862 and the business thrived until 1899, when it ceased operation, with only John Lamb Lyon left alive. Ferguson and Urie was the most successful Nineteenth Century Australian stained glass window making company. Among their earliest works were a Shakespeare window for the Haymarket Theatre in Bourke Street, a memorial window to Prince Albert in Holy Trinity, Kew, and a set of Apostles for the West Melbourne Presbyterian Church. Their palatial Gothic Revival office building stood at 283 Collins Street from 1875. Ironically, their last major commission, a window depicting “labour”, was installed in the old Melbourne Stock Exchange in Collins Street in 1893 on the eve of the bank crash. Their windows can be found throughout the older suburbs of Melbourne and across provincial Victoria.

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . this is not in a zoo - it is wildlife! One hit with their giant claws and you are damaged! Luckily they are not aggressive . . .

__________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . this is not in a zoo - it is wildlife! One hit with their giant claws and you are damaged! Luckily they are not aggressive . . .

__________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . yes, this is in wildlife! And they grow up to 3 meter!

______________________________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . this is not in a zoo - it is wildlife! One hit with their giant claws and you are damaged! Luckily they are not aggressive . . .

__________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . this is not in a zoo - it is wildlife! One hit with their giant claws and you are damaged! Luckily they are not aggressive . . .

__________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . yes, this is in wildlife! And they grow up to 3 meter!

______________________________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . yes, this is in wildlife! And they grow up to 3 meter!

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The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . this is not in a zoo - it is wildlife! One hit with their giant claws and you are damaged! Luckily they are not aggressive . . .

__________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . this is not in a zoo - it is wildlife! One hit with their giant claws and you are damaged! Luckily they are not aggressive . . .

__________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

“Derrinook”, on the corner of Gellibrand and Manifold Streets in Colac, was originally built as a private hospital for Doctor William Henry Brown (1861 – 1926) in 1900.

Built in the Federation Queen Anne architectural style, “Derrinook” is, unusually for the style, built of timber. Federation Queen Anne architectural style, which was mostly a residential style which was inspired by the Arts and Crafts movement in England, but also encompassed some of the more stylised elements of Art Nouveau, which gave it a much more decorative look. Sprawling across a large block with two street frontages, “Derrinook” has a very complex roofline, a common trait of Federation Queen Anne buildings, aided by a large number of half timbered gables. The former private hospital also has some beautiful Art Nouveau stained glass windows. “Derrinook” has a number of “fish scale” pattern panels decorating its façade above the tall windows. “Fish scales” were very popular thanks to the worldwide craze for all things Japanese in the late Nineteenth and early Twentieth Centuries. “Derrinook” also features very sinewy Art Nouveau fretwork around its bay windows, along its verandahs and employed as decoration on the half timbered gables. This was also common amongst Federation Queen Anne buildings. However it is perhaps “Derrinook’s” many elaborate, tall chimneys capped with ceramic chimney pots where the prevailing, and then fashionable, Art Nouveau decorative style is most apparent. One of the first buildings in Colac to employ electric lighting, “Derrinook” was eventually superceded by the Colac Hospital as a place for medical treatment and recouperation. With the change in fortunes for so many during the Great Depression, “Derrinook” was converted into smaller self-contained flats in 1935 and remains private residences to this day.

Queen Anne style was most popular around the time of Federation. With complex roofline structures, ornamental towers of unusual proportions and undulating facades, many Queen Anne houses fell out of fashion at the beginning of the modern era, and were demolished.

Doctor William Henry Brown was born in Erinth in Kent in 1861 and was educated in both England and Germany. He studied medicine at University College in London. He migrated to Australia in 1885 and originally established a practice in the Victorian Gippsland town of Maffra. In 1891 he moved to Colac where he practiced as a partner with local Doctor T. Foster, before acquiring the practice entirely. Doctor Brown became very well known in Colac as a physician and surgeon, and recognition of his skills spread across the state and across the country. His work gained attention world-wide when he published pieces in various medical journals. With the growth of his renown and his practice, he established “Derrinook” in 1900. When the Great War commenced in 1914, Doctor Brown travelled to various country towns as a representative of the army and acted as a dynamic speaker at recruitment drives, attempting to raise community responsibility and patriotism. His wife Clara (1862 – 1939) also worked enthusiastically for the war effort including for the Red Cross Society. His son, Doctor Arthur Edward Brown (1889 – 1975) followed in his father’s footsteps as a medical practitioner and they two worked in partnership at “Derrinook” after the war. Doctor Brown retired to his beachside Sorrento residence “Kennagh” in 1921 where he continued to play tennis (as he had in Colac where he presided over the tennis club for a number of years as president), and also took up improvement of the local foreshore. He also became a member of the Flinders Shire Council in 1923. He died of heart disease in 1926.

Located approximately 150 kilometres to the south-west of Melbourne, past Geelong is the small Western District city of Colac. The area was originally settled by Europeans in 1837 by pastoralist Hugh Murray. A small community sprung up on the southern shore of a large lake amid the volcanic plains. The community was proclaimed a town, Lake Colac, in 1848, named after the lake upon which it perches. The post office opened in 1848 as Lake Colac and was renamed Colac in 1854 when the city changed its name. The township grew over the years, its wealth generated by the booming grazing industries of the large estates of the Western District and the dairy industry that accompanied it. Colac has a long high street shopping precinct, several churches, botanic gardens, a Masonic hall and a smattering of large properties within its boundaries, showing the conspicuous wealth of the city. Today Colac is still a commercial centre for the agricultural district that surrounds it with a population of around 10,000 people. Although not strictly a tourist town, Colac has many beautiful surviving historical buildings or interest, tree lined streets. Colac is known as “the Gateway to the Otways” (a reference to the Otway Ranges and surrounding forest area that is located just to the south of the town).

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . yes, this is in wildlife! And they grow up to 3 meter!

______________________________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . yes, this is in wildlife! And they grow up to 3 meter!

______________________________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

Created in 1863 as a memorial to Edmund William Johnson Bardin by Melbourne stained glass manufacturer Ferguson and Urie, the Holy Family stained glass window may be found at the north end of the nave, to the right of the ornate baptismal font. The window has a pair on the left. The window depicts the Holy Family. In the foreground, Mary holds Jesus in her lap. To the right stands Mary's pot with the letter M monogrammed upon it, from which springs the Annunciation lily, which represents Mary's purity. Behind them in the mid ground, Joseph sits in prayer looking sombre, perhaps as a result of his dream where an angel told him to flee to Egypt with his family to protect Jesus from King Herod's murderous plans.

Edmund William Johnson Bardin died on the 17th of August 1863 according to the beautiful brass plaque below the Holy Family window dedicated to him. Interestingly enough, whilst he died in Brunswick, he appears not to have been a member of the congregation. Records from the Londonderry Sentinel indicate that he was from Emerald Downs in Queenland. Edmund Bardin was the youngest son of the Reverend Charles Bardin (who was for many years the Rector of Derryloran, Cookstown, Diocese of Armagh in Ireland) and his wife Julia Helena Hodgkinson. His brother Alfred Thackeray Purdon Bardin has a memorial window next to him of the presentation of Jesus at the Temple on the opposite side of the baptismal font in Christ Church, Brunswick.

Christ Church, built almost on the corner of Glenlyon Road and Brunswick Street in Brunswick, is a picturesque slice of Italy in inner city Melbourne. With its elegant proportions, warm yellow stuccoed facade and stylish Romanesque campanile, the church would not look out of place sitting atop a rise in Tuscany, or being the centre of an old walled town. This idea is further enhanced when the single bell rings from the campanile, calling worshipers to prayer.

Christ Church has been constructed in a cruciform plan with a detached campanile. Although not originally intended as such, at its completion, the church became an excellent example of "Villa Rustica" architecture in Australia. Like other churches around the inner city during the boom and bust eras of the mid Nineteenth Century as Melbourne became an established city, the building was built in stages between 1857 and 1875 as money became available to extend and better what was already in existence. Christ Church was dedicated in 1857 when the nave, designed by architects Purchas and Swyer, was completed. The transepts, chancel and vestry were completed between 1863 and 1864 to the designs created by the architects' firm Smith and Watts. The Romanesque style campanile was also designed by Smith and Watts and it completed between 1870 and 1871. A third architect, Frederick Wyatt, was employed to design the apse which was completed in 1875.

Built in Italianate style with overture characteristics of classical Italian country house designs, Christ Church is one of the few examples of what has been coined "Villa Rustica" architecture in Victoria.

Slipping through the front door at the bottom of the campanile, the rich smell of incense from mass envelops visitors. As soon as the double doors which lead into the church proper close behind you, the church provides a quiet refuge from the busy intersection of Glenlyon Road and Brunswick Street outside, and it is quite easy to forget that cars and trams pass by just a few metres away. Walking up the aisle of the nave of Christ Church, light pours over the original wooden pews with their hand embroidered cushions through sets of luminescent stained glass windows by Melbourne manufacturers, Ferguson and Urie, Mathieson and Gibson and Brooks Robinson and Company. A set of fourteen windows from the mid-to-late Nineteenth Century by Ferguson and Urie depicting different saints are especially beautiful, filled with painted glass panes which are as vivid now as when they were created more than one hundred years ago. The floors are still the original dark, richly polished boards that generations of worshipers have walked over since they were first laid. The east transept houses the Lady Chapel, whilst the west transept is consumed by the magnificent 1972 Roger H. Pogson organ built of cedar with tin piping. This replaced the original 1889 Alfred Fuller organ. Beautifully executed carved rood figures watch over the chancel from high, perhaps admiring the marble altar.

Albert Purchas, born in 1825 in Chepstow, Monmouthshire, Wales, was a prominent Nineteenth Century architect who achieved great success for himself in Melbourne. Born to parents Robert Whittlesey Purchas and Marianne Guyon, he migrated to Australia in 1851 to establish himself in the then quickly expanding city of Melbourne, where he set up a small architect's firm in Little Collins Street. He also offered surveying services. His first major building was constructing the mansion "Berkeley Hall" in St Kilda on Princes Street in 1854. The house still exists today. Two years after migrating, Albert designed the layout of the Melbourne General Cemetery in Carlton. It was the first "garden cemetery" in Victoria, and his curvilinear design is still in existence, unaltered, today. In 1854, Albert married Eliza Anne Sawyer (1825 - 1869) in St Kilda. The couple had ten children over their marriage, including a son, Robert, who followed in his father's footsteps as an architect. Albert's brother-in-law, Charles Sawyer joined him in the partnership of Purchas and Sawyer, which existed from 1856 until 1862 in Queens Street. The firm produced more than 140 houses, churches, offices and cemetery buildings including: the nave and transepts of Christ Church St Kilda between 1854 and 1857, "Glenara Homestead"in Bulla in 1857, the Melbourne Savings Bank on the corner of Flinders Lane and Market Street (now demolished) between 1857 and 1858, the Geelong branch of the Bank of Australasia in Malop Street between 1859 and 1860, and Beck's Imperial Hotel in Castlemaine in 1861. When the firm broke up, Albert returned to Little Collins Street, and the best known building he designed during this period was St. George's Presbyterian Church in East St Kilda between 1877 and 1880. The church's tall polychomatic brick bell tower is still a local landmark, even in the times of high rise architecture and development, and St, George's itself is said to be one of his most striking church designs. Socially, Albert was vice president of the Royal Victorian Institute of Architects for many years, before becoming president in 1887. He was also an inventor and philanthropist. Albert died in 1909 at his home in Kew, a wealthy widower and much loved father.

The stained glass firm of Ferguson and Urie was established by Scots James Ferguson (1818 – 1894), James Urie (1828 – 1890) and John Lamb Lyon (1836 – 1916). They were the first known makers of stained glass in Australia. Until the early 1860s, window glass in Melbourne had been clear or plain coloured, and nearly all was imported, but new churches and elaborate buildings created a demand for pictorial windows. The three Scotsmen set up Ferguson and Urie in 1862 and the business thrived until 1899, when it ceased operation, with only John Lamb Lyon left alive. Ferguson and Urie was the most successful Nineteenth Century Australian stained glass window making company. Among their earliest works were a Shakespeare window for the Haymarket Theatre in Bourke Street, a memorial window to Prince Albert in Holy Trinity, Kew, and a set of Apostles for the West Melbourne Presbyterian Church. Their palatial Gothic Revival office building stood at 283 Collins Street from 1875. Ironically, their last major commission, a window depicting “labour”, was installed in the old Melbourne Stock Exchange in Collins Street in 1893 on the eve of the bank crash. Their windows can be found throughout the older suburbs of Melbourne and across provincial Victoria.

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . yes, this is in wildlife! And they grow up to 3 meter!

______________________________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

. . . yes, this is in wildlife! And they grow up to 3 meter!

______________________________________________

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

My maternal Grandparents (in the photo above) migrated to Australia from the Netherlands in 1951, with their 4 young adult children. Although my Grandfather had been a sea captain in the Dutch Merchant navy, in a new land many migrants must take any job they can get...and in the early 1960s he was working as the Winchman at a gold mine north of Bullfinch (which is north of Southern Cross in Western Australia); it was called the Radio Mine, managed by Mr Barr. With his eldest son (my uncle) my Grandfather was also working on claim of their own, where they stayed in big old army tents. My Grandmother kept this corrugated iron house near the mine "as neat as a pin". It was lined with newspaper and hessian and in this harsh dry country must have seemed like a different world after the damp lush pastures of their homeland, Holland. But like many, they were made of tough stuff and took it in their strides, how proud I am of them, in hindsight!

Scanned from a slide in family collection

Amid the brightly coloured non-figurative windows on the northern side of Saint George's Presbyterian Church stands one figurative window. Dedicated to American John Kane Smyth, the window was made by Melbourne stained glass manufacturer Ferguson and Urie. Although there is no date on the window, I believe it was created in the 1890s. The window represents two scenes in the life of Jesus: The Settlement about the Tribute Money, and The Interview with the Rich Young Ruler. The left-hand pane is the Settlement about the Tribute Money window. It features Jesus and a Roman tax collector who demanded money from him and the twelve apostles when they had none to pay. Jesus performs a miracle and the tax is paid with a Drachma coin found in the mouth of a fish by Saint Peter. The window shows Jesus and the tax collector in beautiful and richly coloured clothing amid a green countryside. It contains a Biblical quote from the Book of Matthew XIX - 19 in the bottom dedication panel: "Thou shalt love thy neighbor as thyself."

John Kane Smyth was the Vice-Consul for the United States of America in Melbourne, and he was just one of a number of wealthy Americans who attended services at Saint George's Presbyterian Church. In his honour the top round ventilator window has the American Stars and Stripes in it. Interestingly it features the Thirty-Six Stars and Stripes flag which was well outdated by the time this window as installed. The Thirty-Six Stars and Stripes flag became the official United States Flag on July 4th, 1865 after the admission of Nevada into the union. However it was only to last for two years when Nebraska joined the union. John Kane Smyth served on Saint George's Presbyterian Church's Board of Management for many years and is recognised as having given good service in the Saint George's Presbyterian Church's 1876 - 1926 Jubilee Souvenir Book.

The former Saint George's Presbyterian Church was constructed on a plot of land reserved in Chapel Street for the Presbyterian Church of Victoria in 1866. Initially services were held in a small hall whilst fundraising efforts advanced the erection of a church. The architect Albert Purchas was commissioned to design the church and the foundation stone for the western portion of the nave was finally laid in April 1877 by Sir James McCulloch. The first service was held in the church on the 1st of October 1877. The first clergyman of the former Saint George's Presbyterian Church was the Reverend John Laurence Rentoul (father to world renown and much loved Australian children's book illustrator Ida Rentoul Outhwaite). However, the swelling Presbyterian congregation of St Kilda and its surrounding districts quickly outgrew the initial Saint George's Presbyterian Church building, so Albert Purchas was obliged to re-design and enlarge the church to allow a doubling in capacity. Robert S. Ekins was the contractor and his tender was £3000.00. It is this imposing church building, reopened in 1880, that we see today. The "Australasian Sketcher with Pen and Pencil" noted that the total length of the building was 118 feet and 6 inches (36 metres), by 40 foot (12 metres) wide and that the striking octagonal tower to the north-west was 110ft 6 in high. It perhaps reflected better the wealth and aspirations of the congregation.

The former Saint George's Presbyterian Church is constructed on bluestone foundations and is built in an ornate polychromatic Gothic Revival style in the tradition of English designers like William Butterfield and John L. Pearson. Built of red brick building, it is decorated in contrasting cream bricks and Waurn Ponds freestone dressings. It features a slate roof with prominent roof vents, iron ridge cresting and fleche at the intersection of the nave and transepts. The front facade of the church is dominated by the slender, banded octagonal tower topped by a narrow spire. The entrance features a double arched portal portico. The facade also features a dominant triangular epitrochoidal (curved triangular form) rose window. The church, like its bluestone neighbour All Saints Church of England, is built to a T-shaped plan, with an aisleless nave, broad transepts and internal walls of cream brick, relieved with coloured brickwork. The former Saint George's Presbyterian Church was one of the first major church design in Melbourne in which polychrome brickwork was lavishly employed both externally and internally.

The inside of the former Saint George's Presbyterian Church is equally as grand as the exterior, with ornamental Gothic Revival polychromatic brickwork, a lofty vaulted ceiling, deal and kauri pine joinery and pulpit and reredos of Keene's cement. The building originally contained a complete set of Victorian stained glass windows by well known and successful Melbourne manufacturers Ferguson and Urie, all of which remain intact today except for one of the non-figurative windows which was replaced by a memorial window to Samuel Lyons McKenzie, the congregation’s beloved minister, who served from 1930 to 1948, in 1949. The earliest of the Ferguson and Urie windows are non-figurative windows which feature the distinctive diaper pattern and floral motifs of Fergus and Urie's work, and are often argued to be amongst the finest of their non-figurative designs. The large triple window in the chancel was presented by Lady McCulloch in memory of the ‘loved and dead’. Another, in memory of John Kane Smyth, the Vice-Consul for the United States of America in Melbourne, has the American Stars and Stripes on the top ventilator above it. An organ by Thomas C. Lewis of London, one of the leading 19th century English organ builders, was installed in the south transept in 1882. It was designed to blend with its architectural setting, with pipework styled to avoid the obstruction of windows. The action of this organ was altered in 1935, but the pipework, and the original sound, have been retained.

Over the years many spiritual and social activities were instituted at Saint George’s, Presbyterian Church some of short duration such as the Ladies’ Reading Club which operated between 1888 and 1893. There were segregated Bible classes for young men and women, the Presbyterian Women’s Missionary Union, formed in 1892, a cricket club and a floral guild. Guilds teaching physical culture for girls, boys and young men began in 1904. They were entirely financed by John Maclellan and the idea extended to other denominations throughout Victoria. John Maclellan died in 1936 and the guilds ceased at Saint George’s Presbyterian church through lack of funds although in 1977 the members of the girls’ guild were still holding bi-annual reunions and raising money for charity. Sadly, the Presbyterian congregations may have been large in the Nineteenth Century, but by St George's Presbyterian Church's 110th centenary, its doors had already closed during the week due to dwindling numbers and an ageing congregation as a result of the general decline in church attendances after the Second World War exacerbated by the changing nature of St Kilda and the decrease in numbers of residents living in the vicinity of the church. So it stood, forlorn and empty and seemingly nothing more than a relic of a glorious but bygone religious past. However in 1990, Saint Michael's Grammar School across the road leased the Victorian Heritage listed building during weekdays, and it was eventually sold to them in 2015. It now forms part of the school's performing-arts complex, and it has a wonderful new lease of life.

St George's Presbyterian Church is sometimes hired out for performances, and I had the pleasure of receiving an invitation to hear Handel's Messiah performed there in 2009. The ecclesiastical acoustics made the performance all the more magnificent. I remember as I sat on one of the original (hard) kauri pine pews, I looked around me and admired the stained glass and ornamental brickwork. I tried without success over several subsequent years to gain access to the church's interior, settling for photographs of the exterior instead, but it wasn't until 2018 that I was fortunate enough to gain entry to photograph the church's interior. The former St George's Presbyterian Church was opened up to the public for one Sunday morning only as part of Open House Melbourne in July 2018. It was a fantastic morning, and I am very grateful to the staff who manned the church for the day and watched bemused as I photographed the stained glass extensively and in such detail.

Albert Purchas, born in 1825 in Chepstow, Monmouthshire, Wales, was a prominent Nineteenth Century architect who achieved great success for himself in Melbourne. Born to parents Robert Whittlesey Purchas and Marianne Guyon, he migrated to Australia in 1851 to establish himself in the then quickly expanding city of Melbourne, where he set up a small architect's firm in Little Collins Street. He also offered surveying services. His first major building was constructing the mansion "Berkeley Hall" in St Kilda on Princes Street in 1854. The house still exists today. Two years after migrating, Albert designed the layout of the Melbourne General Cemetery in Carlton. It was the first "garden cemetery" in Victoria, and his curvilinear design is still in existence, unaltered, today. In 1854, Albert married Eliza Anne Sawyer (1825 - 1869) in St Kilda. The couple had ten children over their marriage, including a son, Robert, who followed in his father's footsteps as an architect. Albert's brother-in-law, Charles Sawyer joined him in the partnership of Purchas and Sawyer, which existed from 1856 until 1862 in Queens Street. The firm produced more than 140 houses, churches, offices and cemetery buildings including: the nave and transepts of Christ Church St Kilda between 1854 and 1857, "Glenara Homestead"in Bulla in 1857, the Melbourne Savings Bank on the corner of Flinders Lane and Market Street (now demolished) between 1857 and 1858, the Geelong branch of the Bank of Australasia in Malop Street between 1859 and 1860, and Beck's Imperial Hotel in Castlemaine in 1861. When the firm broke up, Albert returned to Little Collins Street, and the best known building he designed during this period was Saint. George's Presbyterian Church in St Kilda East between 1877 and 1880. The church's tall polychomatic brick bell tower is still a local landmark, even in the times of high rise architecture and development, and Saint, George's itself is said to be one of his most striking church designs. Socially, Albert was vice president of the Royal Victorian Institute of Architects for many years, before becoming president in 1887. He was also an inventor and philanthropist. Albert died in 1909 at his home in Kew, a wealthy widower and much loved father.

The stained glass firm of Ferguson and Urie was established by Scots James Ferguson (1818 – 1894), James Urie (1828 – 1890) and John Lamb Lyon (1836 – 1916). They were the first known makers of stained glass in Australia. Until the early 1860s, window glass in Melbourne had been clear or plain coloured, and nearly all was imported, but new churches and elaborate buildings created a demand for pictorial windows. The three Scotsmen set up Ferguson and Urie in 1862 and the business thrived until 1899, when it ceased operation, with only John Lamb Lyon left alive. Ferguson and Urie was the most successful Nineteenth Century Australian stained glass window making company. Among their earliest works were a Shakespeare window for the Haymarket Theatre in Bourke Street, a memorial window to Prince Albert in Holy Trinity, Kew, and a set of Apostles for the West Melbourne Presbyterian Church. Their palatial Gothic Revival office building stood at 283 Collins Street from 1875. Ironically, their last major commission, a window depicting “labour”, was installed in the old Melbourne Stock Exchange in Collins Street in 1893 on the eve of the bank crash. Their windows can be found throughout the older suburbs of Melbourne and across provincial Victoria.

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

1956 Mercury Montclair at the East Kurrajong Hobby and Car Show. This car has quite a history being imported from Iran when the owner migrated to Australia. He has owned the car for over 50 years, since his mid teens.

Created in the mid-to-late Nineteenth Century by Melbourne stained glass manufacturer Ferguson and Urie, the Saint Simon stained glass window may be found in Lady Chapel in the eastern transept of Christ Church Brunswick.

Saint Simon is often referred to as Simon the Zealot or Simon the Cananite. He was one of the twelve apostles of Jesus. As the patron saint of tanners, curriers and sawyers, so in this depiction, Saint Simon holds in his right hand a long saw with sharp teeth. It is one of his most commonly recognised pieces of iconography along with a ship, a cross and a fish.

This window was erected by James Grice, eldest son of pastoralist, businessman, philanthropist and churchman Richard Grice. Richard was born on October the 30th 1813 in Cumberland, England. The son of William Grice and his wife Sarah, née Parke. he was born into a family who ran a private family bank in Cumberland, built on generations of his family who had begun as farmers in the area before becoming successful businessmen in Cumberland. Richard attended Walker's School in Whitehaven, and gained farming experience on one of his family's properties. However, in his mid twenties, Richard felt that his future did not lie in England, so he set sail to Australia in 1839. He arrived at Adelaide in September 1839 with shepherds and a business partner named Benjamin Heape. They did not stay in Adelaide, and journeyed east to Melbourne where Richard and Benjamin set up an importing and exporting business. Richard decided to explore the idea of pastoral opportunities in the Western District where he successfully raised and bred sheep, going on to become one of the most successful pastoralists in Australia. He expanded his pastoral holdings into Queensland. In 1844 Richard married the daughter of James Hibberson, Anne Lavinia. In 1847 they did a Grand Tour of Europe and then settled in the affluent Melbourne suburb of Fitzroy. They had twelve children. Benjamin returned to England in 1852, so Richard entered into a partnership with Mr. T. J. Sumner, who had worked as a clerk within the original firm. Mr. Sumner's eldest daughter married Richard's son James, and the firm became known as Grice, Sumner & Co. The business flourished and by the mid 1870s the firm held vast grazing properties in Victoria, New South Wales, South Australia and Queensland. Richard died at his home in Fitzroy on November the 4th 1882, survived by his wife and by three sons and four daughters.

Christ Church, built almost on the corner of Glenlyon Road and Brunswick Street in Brunswick, is a picturesque slice of Italy in inner city Melbourne. With its elegant proportions, warm yellow stuccoed facade and stylish Romanesque campanile, the church would not look out of place sitting atop a rise in Tuscany, or being the centre of an old walled town. This idea is further enhanced when the single bell rings from the campanile, calling worshipers to prayer.

Christ Church has been constructed in a cruciform plan with a detached campanile. Although not originally intended as such, at its completion, the church became an excellent example of "Villa Rustica" architecture in Australia. Like other churches around the inner city during the boom and bust eras of the mid Nineteenth Century as Melbourne became an established city, the building was built in stages between 1857 and 1875 as money became available to extend and better what was already in existence. Christ Church was dedicated in 1857 when the nave, designed by architects Purchas and Swyer, was completed. The transepts, chancel and vestry were completed between 1863 and 1864 to the designs created by the architects' firm Smith and Watts. The Romanesque style campanile was also designed by Smith and Watts and it completed between 1870 and 1871. A third architect, Frederick Wyatt, was employed to design the apse which was completed in 1875.

Built in Italianate style with overture characteristics of classical Italian country house designs, Christ Church is one of the few examples of what has been coined "Villa Rustica" architecture in Victoria.

Slipping through the front door at the bottom of the campanile, the rich smell of incense from mass envelops visitors. As soon as the double doors which lead into the church proper close behind you, the church provides a quiet refuge from the busy intersection of Glenlyon Road and Brunswick Street outside, and it is quite easy to forget that cars and trams pass by just a few metres away. Walking up the aisle of the nave of Christ Church, light pours over the original wooden pews with their hand embroidered cushions through sets of luminescent stained glass windows by Melbourne manufacturers, Ferguson and Urie, Mathieson and Gibson and Brooks Robinson and Company. A set of fourteen windows from the mid-to-late Nineteenth Century by Ferguson and Urie depicting different saints are especially beautiful, filled with painted glass panes which are as vivid now as when they were created more than one hundred years ago. The floors are still the original dark, richly polished boards that generations of worshipers have walked over since they were first laid. The east transept houses the Lady Chapel, whilst the west transept is consumed by the magnificent 1972 Roger H. Pogson organ built of cedar with tin piping. This replaced the original 1889 Alfred Fuller organ. Beautifully executed carved rood figures watch over the chancel from high, perhaps admiring the marble altar.

Albert Purchas, born in 1825 in Chepstow, Monmouthshire, Wales, was a prominent Nineteenth Century architect who achieved great success for himself in Melbourne. Born to parents Robert Whittlesey Purchas and Marianne Guyon, he migrated to Australia in 1851 to establish himself in the then quickly expanding city of Melbourne, where he set up a small architect's firm in Little Collins Street. He also offered surveying services. His first major building was constructing the mansion "Berkeley Hall" in St Kilda on Princes Street in 1854. The house still exists today. Two years after migrating, Albert designed the layout of the Melbourne General Cemetery in Carlton. It was the first "garden cemetery" in Victoria, and his curvilinear design is still in existence, unaltered, today. In 1854, Albert married Eliza Anne Sawyer (1825 - 1869) in St Kilda. The couple had ten children over their marriage, including a son, Robert, who followed in his father's footsteps as an architect. Albert's brother-in-law, Charles Sawyer joined him in the partnership of Purchas and Sawyer, which existed from 1856 until 1862 in Queens Street. The firm produced more than 140 houses, churches, offices and cemetery buildings including: the nave and transepts of Christ Church St Kilda between 1854 and 1857, "Glenara Homestead"in Bulla in 1857, the Melbourne Savings Bank on the corner of Flinders Lane and Market Street (now demolished) between 1857 and 1858, the Geelong branch of the Bank of Australasia in Malop Street between 1859 and 1860, and Beck's Imperial Hotel in Castlemaine in 1861. When the firm broke up, Albert returned to Little Collins Street, and the best known building he designed during this period was St. George's Presbyterian Church in East St Kilda between 1877 and 1880. The church's tall polychomatic brick bell tower is still a local landmark, even in the times of high rise architecture and development, and St, George's itself is said to be one of his most striking church designs. Socially, Albert was vice president of the Royal Victorian Institute of Architects for many years, before becoming president in 1887. He was also an inventor and philanthropist. Albert died in 1909 at his home in Kew, a wealthy widower and much loved father.

The stained glass firm of Ferguson and Urie was established by Scots James Ferguson (1818 – 1894), James Urie (1828 – 1890) and John Lamb Lyon (1836 – 1916). They were the first known makers of stained glass in Australia. Until the early 1860s, window glass in Melbourne had been clear or plain coloured, and nearly all was imported, but new churches and elaborate buildings created a demand for pictorial windows. The three Scotsmen set up Ferguson and Urie in 1862 and the business thrived until 1899, when it ceased operation, with only John Lamb Lyon left alive. Ferguson and Urie was the most successful Nineteenth Century Australian stained glass window making company. Among their earliest works were a Shakespeare window for the Haymarket Theatre in Bourke Street, a memorial window to Prince Albert in Holy Trinity, Kew, and a set of Apostles for the West Melbourne Presbyterian Church. Their palatial Gothic Revival office building stood at 283 Collins Street from 1875. Ironically, their last major commission, a window depicting “labour”, was installed in the old Melbourne Stock Exchange in Collins Street in 1893 on the eve of the bank crash. Their windows can be found throughout the older suburbs of Melbourne and across provincial Victoria.

Amid the brightly coloured non-figurative windows on the northern side of Saint George's Presbyterian Church stands one figurative window. Dedicated to American John Kane Smyth, the window was made by Melbourne stained glass manufacturer Ferguson and Urie. Although there is no date on the window, I believe it was created in the 1890s. The window represents two scenes in the life of Jesus: The Settlement about the Tribute Money, and The Interview with the Rich Young Ruler. The left-hand pane is the Settlement about the Tribute Money window. It features Jesus and a Roman tax collector who demanded money from him and the twelve apostles when they had none to pay. Jesus performs a miracle and the tax is paid with a Drachma coin found in the mouth of a fish by Saint Peter. The window shows Jesus and the tax collector in beautiful and richly coloured clothing amid a green countryside. It contains a Biblical quote from the Book of Matthew XIX - 19 in the bottom dedication panel: "Thou shalt love thy neighbor as thyself."

John Kane Smyth was the Vice-Consul for the United States of America in Melbourne, and he was just one of a number of wealthy Americans who attended services at Saint George's Presbyterian Church. In his honour the top round ventilator window has the American Stars and Stripes in it. Interestingly it features the Thirty-Six Stars and Stripes flag which was well outdated by the time this window as installed. The Thirty-Six Stars and Stripes flag became the official United States Flag on July 4th, 1865 after the admission of Nevada into the union. However it was only to last for two years when Nebraska joined the union. John Kane Smyth served on Saint George's Presbyterian Church's Board of Management for many years and is recognised as having given good service in the Saint George's Presbyterian Church's 1876 - 1926 Jubilee Souvenir Book.

The former Saint George's Presbyterian Church was constructed on a plot of land reserved in Chapel Street for the Presbyterian Church of Victoria in 1866. Initially services were held in a small hall whilst fundraising efforts advanced the erection of a church. The architect Albert Purchas was commissioned to design the church and the foundation stone for the western portion of the nave was finally laid in April 1877 by Sir James McCulloch. The first service was held in the church on the 1st of October 1877. The first clergyman of the former Saint George's Presbyterian Church was the Reverend John Laurence Rentoul (father to world renown and much loved Australian children's book illustrator Ida Rentoul Outhwaite). However, the swelling Presbyterian congregation of St Kilda and its surrounding districts quickly outgrew the initial Saint George's Presbyterian Church building, so Albert Purchas was obliged to re-design and enlarge the church to allow a doubling in capacity. Robert S. Ekins was the contractor and his tender was £3000.00. It is this imposing church building, reopened in 1880, that we see today. The "Australasian Sketcher with Pen and Pencil" noted that the total length of the building was 118 feet and 6 inches (36 metres), by 40 foot (12 metres) wide and that the striking octagonal tower to the north-west was 110ft 6 in high. It perhaps reflected better the wealth and aspirations of the congregation.

The former Saint George's Presbyterian Church is constructed on bluestone foundations and is built in an ornate polychromatic Gothic Revival style in the tradition of English designers like William Butterfield and John L. Pearson. Built of red brick building, it is decorated in contrasting cream bricks and Waurn Ponds freestone dressings. It features a slate roof with prominent roof vents, iron ridge cresting and fleche at the intersection of the nave and transepts. The front facade of the church is dominated by the slender, banded octagonal tower topped by a narrow spire. The entrance features a double arched portal portico. The facade also features a dominant triangular epitrochoidal (curved triangular form) rose window. The church, like its bluestone neighbour All Saints Church of England, is built to a T-shaped plan, with an aisleless nave, broad transepts and internal walls of cream brick, relieved with coloured brickwork. The former Saint George's Presbyterian Church was one of the first major church design in Melbourne in which polychrome brickwork was lavishly employed both externally and internally.

The inside of the former Saint George's Presbyterian Church is equally as grand as the exterior, with ornamental Gothic Revival polychromatic brickwork, a lofty vaulted ceiling, deal and kauri pine joinery and pulpit and reredos of Keene's cement. The building originally contained a complete set of Victorian stained glass windows by well known and successful Melbourne manufacturers Ferguson and Urie, all of which remain intact today except for one of the non-figurative windows which was replaced by a memorial window to Samuel Lyons McKenzie, the congregation’s beloved minister, who served from 1930 to 1948, in 1949. The earliest of the Ferguson and Urie windows are non-figurative windows which feature the distinctive diaper pattern and floral motifs of Fergus and Urie's work, and are often argued to be amongst the finest of their non-figurative designs. The large triple window in the chancel was presented by Lady McCulloch in memory of the ‘loved and dead’. Another, in memory of John Kane Smyth, the Vice-Consul for the United States of America in Melbourne, has the American Stars and Stripes on the top ventilator above it. An organ by Thomas C. Lewis of London, one of the leading 19th century English organ builders, was installed in the south transept in 1882. It was designed to blend with its architectural setting, with pipework styled to avoid the obstruction of windows. The action of this organ was altered in 1935, but the pipework, and the original sound, have been retained.

Over the years many spiritual and social activities were instituted at Saint George’s, Presbyterian Church some of short duration such as the Ladies’ Reading Club which operated between 1888 and 1893. There were segregated Bible classes for young men and women, the Presbyterian Women’s Missionary Union, formed in 1892, a cricket club and a floral guild. Guilds teaching physical culture for girls, boys and young men began in 1904. They were entirely financed by John Maclellan and the idea extended to other denominations throughout Victoria. John Maclellan died in 1936 and the guilds ceased at Saint George’s Presbyterian church through lack of funds although in 1977 the members of the girls’ guild were still holding bi-annual reunions and raising money for charity. Sadly, the Presbyterian congregations may have been large in the Nineteenth Century, but by St George's Presbyterian Church's 110th centenary, its doors had already closed during the week due to dwindling numbers and an ageing congregation as a result of the general decline in church attendances after the Second World War exacerbated by the changing nature of St Kilda and the decrease in numbers of residents living in the vicinity of the church. So it stood, forlorn and empty and seemingly nothing more than a relic of a glorious but bygone religious past. However in 1990, Saint Michael's Grammar School across the road leased the Victorian Heritage listed building during weekdays, and it was eventually sold to them in 2015. It now forms part of the school's performing-arts complex, and it has a wonderful new lease of life.

St George's Presbyterian Church is sometimes hired out for performances, and I had the pleasure of receiving an invitation to hear Handel's Messiah performed there in 2009. The ecclesiastical acoustics made the performance all the more magnificent. I remember as I sat on one of the original (hard) kauri pine pews, I looked around me and admired the stained glass and ornamental brickwork. I tried without success over several subsequent years to gain access to the church's interior, settling for photographs of the exterior instead, but it wasn't until 2018 that I was fortunate enough to gain entry to photograph the church's interior. The former St George's Presbyterian Church was opened up to the public for one Sunday morning only as part of Open House Melbourne in July 2018. It was a fantastic morning, and I am very grateful to the staff who manned the church for the day and watched bemused as I photographed the stained glass extensively and in such detail.

Albert Purchas, born in 1825 in Chepstow, Monmouthshire, Wales, was a prominent Nineteenth Century architect who achieved great success for himself in Melbourne. Born to parents Robert Whittlesey Purchas and Marianne Guyon, he migrated to Australia in 1851 to establish himself in the then quickly expanding city of Melbourne, where he set up a small architect's firm in Little Collins Street. He also offered surveying services. His first major building was constructing the mansion "Berkeley Hall" in St Kilda on Princes Street in 1854. The house still exists today. Two years after migrating, Albert designed the layout of the Melbourne General Cemetery in Carlton. It was the first "garden cemetery" in Victoria, and his curvilinear design is still in existence, unaltered, today. In 1854, Albert married Eliza Anne Sawyer (1825 - 1869) in St Kilda. The couple had ten children over their marriage, including a son, Robert, who followed in his father's footsteps as an architect. Albert's brother-in-law, Charles Sawyer joined him in the partnership of Purchas and Sawyer, which existed from 1856 until 1862 in Queens Street. The firm produced more than 140 houses, churches, offices and cemetery buildings including: the nave and transepts of Christ Church St Kilda between 1854 and 1857, "Glenara Homestead"in Bulla in 1857, the Melbourne Savings Bank on the corner of Flinders Lane and Market Street (now demolished) between 1857 and 1858, the Geelong branch of the Bank of Australasia in Malop Street between 1859 and 1860, and Beck's Imperial Hotel in Castlemaine in 1861. When the firm broke up, Albert returned to Little Collins Street, and the best known building he designed during this period was Saint. George's Presbyterian Church in St Kilda East between 1877 and 1880. The church's tall polychomatic brick bell tower is still a local landmark, even in the times of high rise architecture and development, and Saint, George's itself is said to be one of his most striking church designs. Socially, Albert was vice president of the Royal Victorian Institute of Architects for many years, before becoming president in 1887. He was also an inventor and philanthropist. Albert died in 1909 at his home in Kew, a wealthy widower and much loved father.

The stained glass firm of Ferguson and Urie was established by Scots James Ferguson (1818 – 1894), James Urie (1828 – 1890) and John Lamb Lyon (1836 – 1916). They were the first known makers of stained glass in Australia. Until the early 1860s, window glass in Melbourne had been clear or plain coloured, and nearly all was imported, but new churches and elaborate buildings created a demand for pictorial windows. The three Scotsmen set up Ferguson and Urie in 1862 and the business thrived until 1899, when it ceased operation, with only John Lamb Lyon left alive. Ferguson and Urie was the most successful Nineteenth Century Australian stained glass window making company. Among their earliest works were a Shakespeare window for the Haymarket Theatre in Bourke Street, a memorial window to Prince Albert in Holy Trinity, Kew, and a set of Apostles for the West Melbourne Presbyterian Church. Their palatial Gothic Revival office building stood at 283 Collins Street from 1875. Ironically, their last major commission, a window depicting “labour”, was installed in the old Melbourne Stock Exchange in Collins Street in 1893 on the eve of the bank crash. Their windows can be found throughout the older suburbs of Melbourne and across provincial Victoria.

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, and Padar. A member of the monitor lizard family Varanidae, it is the largest living species of lizard, growing to a maximum length of 3 metres in rare cases and weighing up to approximately 70 kilograms.

Their unusually large size has been attributed to island gigantism, since no other carnivorous animals fill the niche on the islands where they live. However, recent research suggests the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka [kiloannums]."

As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. It has been claimed that they have a venomous bite; there are two glands in the lower jaw which secrete several toxic proteins. The biological significance of these proteins is disputed, but the glands have been shown to secrete an anticoagulant. Komodo dragon group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. Komodo dragons also occasionally attack humans in the area of West Manggarai Regency where they live in Indonesia.

Mating begins between May and August, and the eggs are laid in September. About 20 eggs are deposited in abandoned megapode nests or in a self-dug nesting hole. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. Young Komodo dragons are vulnerable and therefore dwell in trees, safe from predators and cannibalistic adults. They take 8 to 9 years to mature, and are estimated to live up to 30 years.

Komodo dragons were first recorded by Western scientists in 1910. Their large size and fearsome reputation make them popular zoo exhibits. In the wild, their range has contracted due to human activities, and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

ETYMOLOGY

The Komodo dragon is also known as the Komodo monitor or the Komodo Island monitor in scientific literature, although this is not very common. To the natives of Komodo Island, it is referred to as ora, buaya darat (land crocodile), or biawak raksasa (giant monitor).

EVOLUTIONARY HISTORY

The evolutionary development of the Komodo dragon started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia. Around 15 million years ago, a collision between Australia and Southeast Asia allowed the varanids to move into what is now the Indonesian archipelago, extending their range as far east as the island of Timor. The Komodo dragon was believed to have differentiated from its Australian ancestors 4 million years ago. However, recent fossil evidence from Queensland suggests the Komodo dragon evolved in Australia before spreading to Indonesia. Dramatic lowering of sea level during the last glacial period uncovered extensive stretches of continental shelf that the Komodo dragon colonized, becoming isolated in their present island range as sea levels rose afterwards.

DESCRIPTION

In the wild, an adult Komodo dragon usually weighs around 70 kg, although captive specimens often weigh more. According to the Guinness Book of World Records, an average adult male will weigh 79 to 91 kg and measure 2.59 m, while an average female will weigh 68 to 73 kg and measure 2.29 m. The largest verified wild specimen was 3.13 m long and weighed 166 kg, including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced, serrated teeth that can measure up to 2.5 cm in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue. Komodo dragon skin is reinforced by armoured scales, which contain tiny bones called osteoderms that function as a sort of natural chain-mail. This rugged hide makes Komodo dragon skin poorly suited for making into leather.

SENSES

As with other Varanids, Komodo dragons have only a single ear bone, the stapes, for transferring vibrations from the tympanic membrane to the cochlea. This arrangement means they are likely restricted to sounds in the 400 to 2,000 hertz range, compared to humans who hear between 20 and 20,000 hertz. It was formerly thought to be deaf when a study reported no agitation in wild Komodo dragons in response to whispers, raised voices, or shouts. This was disputed when London Zoological Garden employee Joan Proctor trained a captive specimen to come out to feed at the sound of her voice, even when she could not be seen.

The Komodo dragon can see objects as far away as 300 m, but because its retinas only contain cones, it is thought to have poor night vision. The Komodo dragon is able to see in color, but has poor visual discrimination of stationary objects.

The Komodo dragon uses its tongue to detect, taste, and smell stimuli, as with many other reptiles, with the vomeronasal sense using the Jacobson's organ, rather than using the nostrils. With the help of a favorable wind and its habit of swinging its head from side to side as it walks, a Komodo dragon may be able to detect carrion from 4–9.5 km away. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves to facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.

BEHAVIOUR AND ECOLOGY

The Komodo dragon prefers hot and dry places, and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an ectotherm, it is most active in the day, although it exhibits some nocturnal activity. Komodo dragons are solitary, coming together only to breed and eat. They are capable of running rapidly in brief sprints up to 20 km/h, diving up to 4.5 m, and climbing trees proficiently when young through use of their strong claws. To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.

For shelter, the Komodo dragon digs holes that can measure from 1–3 m wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimize its basking period the morning after. The Komodo dragon hunts in the afternoon, but stays in the shade during the hottest part of the day. These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.

DIET

Komodo dragons are carnivores. Although they eat mostly carrion, they will also ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal and go for the underside or the throat. It is able to locate its prey using its keen sense of smell, which can locate a dead or dying animal from a range of up to 9.5 km. Komodo dragons have been observed knocking down large pigs and deer with their strong tails.

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The vegetable contents of the stomach and intestines are typically avoided. Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20 minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully, the tree is knocked down. To prevent itself from suffocating while swallowing, it breathes using a small tube under the tongue that connects to the lungs. After eating up to 80% of its body weight in one meal, it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested for too long. Because of their slow metabolism, large dragons can survive on as little as 12 meals a year. After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus, suggesting, like humans, it does not relish the scent of its own excretions.

The largest animals eat first, while the smaller ones follow a hierarchy. The largest male asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.

The Komodo dragon's diet is wide-ranging, and includes invertebrates, other reptiles (including smaller Komodo dragons), birds, bird eggs, small mammals, monkeys, wild boar, goats, deer, horses, and water buffalo. Young Komodos will eat insects, eggs, geckos, and small mammals. Occasionally, they consume humans and human corpses, digging up bodies from shallow graves. This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground and pile rocks on top of them to deter the lizards. The Komodo dragon may have evolved to feed on the extinct dwarf elephant Stegodon that once lived on Flores, according to evolutionary biologist Jared Diamond.

The Komodo dragon drinks by sucking water into its mouth via buccal pumping (a process also used for respiration), lifting its head, and letting the water run down its throat.

SALIVA

Auffenberg described the Komodo dragon as having septic pathogens in its saliva (he described the saliva as "reddish and copious"), specifically the bacteria E. coli, Staphylococcus sp., Providencia sp., Proteus morgani, and P. mirabilis. He noted, while these pathogens can be found in the mouths of wild Komodo dragons, they disappear from the mouths of captive animals, due to cleaner diets and the use of antibiotics. This was verified by taking mucous samples from the external gum surfaces of the upper jaws of two freshly captured individuals. Saliva samples were analyzed by researchers at the University of Texas, who found 57 strains of bacteria growing in the mouths of three wild Komodo dragons, including Pasteurella multocida. The rapid growth of these bacteria was noted by Fredeking: "Normally it takes about three days for a sample of P. multocida to cover a Petri dish; ours took eight hours. We were very taken aback by how virulent these strains were". This study supported the observation that wounds inflicted by the Komodo dragon are often associated with sepsis and subsequent infections in prey animals. How the Komodo dragon is unaffected by these virulent bacteria remains a mystery.Research in 2013 suggested that the bacteria in the mouths of komodo dragons are ordinary and similar to those found in other carnivores. They actually have surprisingly good mouth hygiene. As Bryan Fry put it: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." The observation of prey dying of sepsis would then be explained by the natural instinct of water buffalos, who are not native to the islands where the Komodo dragon lives, to run into water when attacked. The warm, feces filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three U.S. zoos.

VENOM

In late 2005, researchers at the University of Melbourne speculated the perentie (Varanus giganteus), other species of monitors, and agamids may be somewhat venomous. The team believes the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a lace monitor (V. varius), a Komodo dragon, and a spotted tree monitor (V. scalaris) all produced similar effects: rapid swelling, localized disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.

In 2009, the same researchers published further evidence demonstrating Komodo dragons possess a venomous bite. MRI scans of a preserved skull showed the presence of two glands in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill specimen in the Singapore Zoological Gardens, and found it secreted several different toxic proteins. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey. As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.

Kurt Schwenk, an evolutionary biologist at the University of Connecticut, finds the discovery of these glands intriguing, but considers most of the evidence for venom in the study to be "meaningless, irrelevant, incorrect or falsely misleading". Even if the lizards have venom-like proteins in their mouths, Schwenk argues, they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.

Other scientists such as Washington State University's Biologist Kenneth V. Kardong and Toxicologists Scott A. Weinstein and Tamara L. Smith, have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution". According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey". These researchers concluded that, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems".

REPRODUCTION

Mating occurs between May and August, with the eggs laid in September. During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight. The winner of the fight will then flick his long tongue at the female to gain information about her receptivity. Females are antagonistic and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking. Copulation occurs when the male inserts one of his hemipenes into the female's cloaca. Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards. Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of orange-footed scrubfowl (a moundbuilder or megapode), 20% on ground level and 20% in hilly areas. The females make many camouflage nests/holes to prevent other dragons from eating the eggs. Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months. Hatching is an exhausting effort for the neonates, which break out of their eggshells with an egg tooth that falls off soon after. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation. Sixteen youngsters from a single nest were on average 46.5 cm long and weighed 105.1 grams. Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets. The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare. When the young approach a kill, they roll around in fecal matter and rest in the intestines of eviscerated animals to deter these hungry adults. Komodo dragons take approximately three to five years to mature, and may live for up to 50 years.

PARTHENOGENESIS

A Komodo dragon at London Zoo named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store sperm from her earlier encounter with a male, an adaptation known as superfecundation. On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the Chester Zoo in England, was the second known Komodo dragon to have laid unfertilized eggs: she laid 11 eggs, and seven of them hatched, all of them male. Scientists at Liverpool University in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization. On 31 January 2008, the Sedgwick County Zoo in Wichita, Kansas, became the first zoo in the Americas to document parthenogenesis in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.

Komodo dragons have the ZW chromosomal sex-determination system, as opposed to the mammalian XY system. Male progeny prove Flora's unfertilized eggs were haploid (n) and doubled their chromosomes later to become diploid (2n) (by being fertilized by a polar body, or by chromosome duplication without cell division), rather than by her laying diploid eggs by one of the meiosis reduction-divisions in her ovaries failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z chromosome become ZZ (male); those receiving a W chromosome become WW and fail to develop, meaning that only males are produced by parthenogenesis in this species.

It has been hypothesized that this reproductive adaptation allows a single female to enter an isolated ecological niche (such as an island) and by parthenogenesis produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young). Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.

HISTORY

DISCOVERY BY THE WESTERN WORLD

Komodo dragons were first documented by Europeans in 1910, when rumors of a "land crocodile" reached Lieutenant van Steyn van Hensbroek of the Dutch colonial administration. Widespread notoriety came after 1912, when Peter Ouwens, the director of the Zoological Museum at Bogor, Java, published a paper on the topic after receiving a photo and a skin from the lieutenant, as well as two other specimens from a collector. The first two live Komodo dragons to arrive in Europe were exhibited in the Reptile House at London Zoo when it opened in 1927. Joan Beauchamp Procter made some of the earliest observations of these animals in captivity and she demonstrated the behaviour of one of these animals at a Scientific Meeting of the Zoological Society of London in 1928. The Komodo dragon was the driving factor for an expedition to Komodo Island by W. Douglas Burden in 1926. After returning with 12 preserved specimens and 2 live ones, this expedition provided the inspiration for the 1933 movie King Kong. It was also Burden who coined the common name "Komodo dragon." Three of his specimens were stuffed and are still on display in the American Museum of Natural History.

STUDIES

The Dutch, realizing the limited number of individuals in the wild, outlawed sport hunting and heavily limited the number of individuals taken for scientific study. Collecting expeditions ground to a halt with the occurrence of World War II, not resuming until the 1950s and 1960s, when studies examined the Komodo dragon's feeding behavior, reproduction, and body temperature. At around this time, an expedition was planned in which a long-term study of the Komodo dragon would be undertaken. This task was given to the Auffenberg family, who stayed on Komodo Island for 11 months in 1969. During their stay, Walter Auffenberg and his assistant Putra Sastrawan captured and tagged more than 50 Komodo dragons. The research from the Auffenberg expedition would prove to be enormously influential in raising Komodo dragons in captivity. Research after that of the Auffenberg family has shed more light on the nature of the Komodo dragon, with biologists such as Claudio Ciofi continuing to study the creatures.

CONSERVATION

The Komodo dragon is a vulnerable species and is on the IUCN Red List. There are approximately 4,000 to 5,000 living Komodo dragons in the wild. Their populations are restricted to the islands of Gili Motang (100), Gili Dasami (100), Rinca (1,300), Komodo (1,700), and Flores (perhaps 2,000). However, there are concerns that there may presently be only 350 breeding females. To address these concerns, the Komodo National Park was founded in 1980 to protect Komodo dragon populations on islands including Komodo, Rinca, and Padar. Later, the Wae Wuul and Wolo Tado Reserves were opened on Flores to aid with Komodo dragon conservation.

Komodo dragons avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres. Older animals will also retreat from humans from a shorter distance away. If cornered, they will react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may start an attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or caused by defensive bites. Only a very few cases are truly the result of unprovoked attacks by abnormal individuals, which lost their fear towards humans.

Volcanic activity, earthquakes, loss of habitat, fire, loss of prey due to poaching, tourism, and illegal poaching of the dragons themselves have all contributed to the vulnerable status of the Komodo dragon. Under Appendix I of CITES (the Convention on International Trade in Endangered Species), commercial trade of skins or specimens is illegal.

On Padar, a former population of the Komodo dragon became extinct, of which the last individuals were seen in 1975. It is widely assumed that the Komodo dragon died out on Padar after a strong decline of the populations of large ungulate prey, for which poaching was most likely responsible.

IN CAPTIVITY

Komodo dragons have long been great zoo attractions, where their size and reputation make them popular exhibits. They are, however, rare in zoos because they are susceptible to infection and parasitic disease if captured from the wild, and do not readily reproduce. As of May 2009, there were 13 European, 2 African, 35 North American, 1 Singaporean, and 2 Australian institutions that kept Komodo dragons.

The first Komodo dragons were displayed at London Zoo in 1927. A Komodo dragon was exhibited in 1934 at the National Zoo in Washington, D.C., but it lived for only two years. More attempts to exhibit Komodo dragons were made, but the lifespan of these animals was very short, averaging five years in the National Zoological Park. Studies done by Walter Auffenberg, which were documented in his book The Behavioral Ecology of the Komodo Monitor, eventually allowed for more successful managing and reproducing of the dragons in captivity.

A variety of behaviors have been observed from captive specimens. Most individuals are relatively tame within a short time, and are capable of recognizing individual humans and discriminating between familiar keepers. Komodo dragons have also been observed to engage in play with a variety of objects, including shovels, cans, plastic rings, and shoes. This behavior does not seem to be "food-motivated predatory behavior".

Even seemingly docile dragons may become unpredictably aggressive, especially when the animal's territory is invaded by someone unfamiliar. In June 2001, a Komodo dragon seriously injured Phil Bronstein, the then husband of actress Sharon Stone, when he entered its enclosure at the Los Angeles Zoo after being invited in by its keeper. Bronstein was bitten on his bare foot, as the keeper had told him to take off his white shoes and socks, which the keeper stated could potentially excite the Komodo dragon as they were the same color as the white rats the zoo fed the dragon. Although he escaped, Bronstein needed to have several tendons in his foot reattached surgically.

IN POPULARE CULTURE

Komodo dragons are used as a main theme in Komodo (1999), Curse of the Komodo (2004) and Komodo vs. Cobra (2005).

The comedy team of Bob and Ray performed a popular sketch entitled "The Komodo Dragon Expert."

The plot of the 1990 film, The Freshman, involves a university freshman, an aging mobster and a Komodo dragon.

In the 2012 James Bond film Skyfall, one of the Chinese henchmen in a casino that Bond visits in Macau is overtaken, dragged off and presumably killed by a Komodo dragon.

WIKIPEDIA

George Bills was an Englishman who migrated to Australia, via New Zealand. In Brisbane he met and married Annis Swann from Sheffield, England. The couple had no children but shared a great interest in animal welfare. They ended up in Sydney making a fortune manufacturing mattresses. One thing they thought was important was to see that when a horse came into town there was somewhere for the horse to drink: some also had a dog bowl at the end.

After George's death in 1927 a trust fund of approximately £80,000 was set to manufacture and provide horse troughs wherever they were needed in Australia and the United Kingdom – hence the "Annis and George Bills" trough. Most troughs read "Donated by Annis & George Bills Australia".

The troughs were £13 each plus transport and installation. The majority were installed in Victoria and New South Wales. One exists at St Arnaud, Victoria, another at Newtown, Victoria. One is also at Tunbridge Wells UK.

Reference: ABC Real Stories website and Wikipedia.