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One of many unfortunate birds at Saigon Zoo.... They seriously need to expand captivity cage that allows such big birds more room to fly around.
Changeable Hawk-Eagle (Nisaetus cirrhatus)
The changeable hawk-eagle or crested hawk-eagle (Nisaetus cirrhatus) is a bird of prey species of the family Accipitridae. It was formerly placed in the genus Spizaetus, but studies pointed to the group being paraphyletic resulting in the Old World members being placed in Nisaetus (Hodgson, 1836) and separated from the New World species.
Changeable hawk-eagles breed in the Indian subcontinent, mainly in India and Sri Lanka, and from the southeast rim of the Himalaya across Southeast Asia to Indonesia and the Philippines. This is a bird occurring singly (outside mating season) in open woodland, although island forms prefer a higher tree density. It builds a stick nest in a tree and lays a single egg.
Description
The changeable hawk-eagle is a medium-large raptor at about 60–72 centimetres (24–28 in) in length with a 127–138 centimetres (50–54 in) wingspan, and a weight ranging from 1.2 to 1.9 kg.[3] It is a relatively slender forest eagle with some subspecies (especially N. c. limnaetus) being dimorphic giving the name "changeable". This and their complicated phylogeny further complicate precise identification.
Normally brown above, they have white below with barring on the undersides of the flight feathers and tail; black longitudinal streaks occur on the throat and chocolate streaks occur on the breast. Some subspecies have a crest of four feathers, but this is all but absent in others. The sexes are quite similar in their plumage, but males are about 15% smaller than females. The underparts and head of juveniles are whitish or buff with few dark streaks.
The wings are long and parallel-sided, and are held flat in flight, which helps to distinguish this species from the similar mountain hawk-eagle. In overhead flight, comparatively rounded wings (upturned at tip), longish tail, white body (spotted with brown) and grey underside of wings (streaked and spotted) are leading pointers.
Their call is a loud, high-pitched ki-ki-ki-ki-ki-ki-ki-ki-kee, beginning short, rising in crescendo, and ending in a scream.
Ecology
Changeable hawk-eagles eat mammals, birds, and reptiles. They keep a sharp lookout perched bolt upright on a bough amongst the canopy foliage of some high tree standing near a forest clearing. There, they wait for junglefowl, pheasants, hares, and other small animals coming out into the open. The bird then swoops down forcefully, strikes, and bears the prey away in its talons.
Nesting
Season: December to April
Nest: a large stick platform lined with green leaves, high up in a forest tree
Eggs: a single one, greyish white, unmarked or with faint specks and blotches of light reddish at the broad end
Systematics
The Flores hawk-eagle has traditionally been treated as a subspecies of the changeable hawk-eagle, but it is now often treated as a separate species, N. floris.
Two distinct groups exist in the changeable hawk-eagle; one with crests and one without or with hardly visible crests. Dark morphs exist for some populations.
Changeable hawk-eagle
N. c. cirrhatus
- Gangetic plain southwards throughout India
- Crested, no dark morph
N. c. ceylanensis
- Sri Lanka (possibly also Travancore)
- Smaller than nominate, crest proportionally longer on average, apparently no dark morph
Crestless changeable hawk-eagle
N. c. limnaeetus
- Nepal, northeast India, via Burma and Malay Peninsula along Wallace Line to Philippines
- Much like nominate except crest, dimorphic, with the dark morph chocolate-brown all over, tail base might appear lighter in flight
N. c. andamanensis
- Andaman Islands
- Similar to N. c. limnaeetus, apparently no dark morph
N. c. vanheurni
- Simeulue Island
- Similar to N. c. limnaeetus, apparently no dark morph
Gamauf et al. (2005) analyzed mtDNA cytochrome b and control region sequence data of a considerable number of specimens of the crested hawk-eagle and some relatives. Despite the large sample, even the most conspicuous dichotomy - that between the crested and crestless groups - was not as well resolved as it might have been expected to be.
The three small-island taxa (N. c. andamanensis, N. c. vanheurni, and N. floris) also appear as monophyletic lineages. Their placement is even more unresolved, with N. floris being apparently a very ancient lineage. The other two seem quite certainly to derive from N. c. limnaeetus. The latter taxon has a confusing phylogeny. Different lineages exist that are apparently not stable in space and time, are best described as polytomy, from which the similar island taxa derive.
Obviously, N. c. limnaeetus does not represent a monophyletic lineage. Neither the biological nor the phylogenetic species concepts, nor phylogenetic systematics can be applied to satisfaction. The crested group apparently is close to becoming a distinct species. The island taxa derived from N. c. limnaeetus appear to have undergone founder effects, which has restricted their genetic diversity. In the continental population, genetic diversity is considerable, and the evolutionary pattern of the two studied genes did not agree, and neither did the origin of specimens show clear structures. N. c. limnaeetus thus is best considered a metapopulation.
Gamauf et al. (2005) therefore suggest the island taxa which are obviously at higher risk of extinction are, for conservation considered evolutionary significant units regardless of their systematic status. This case also demonstrates that a too-rigid interpretation of cladistics and the desire for monophyletic taxa, as well as universal application of single-species concept to all birds will undermine correct understanding of evolutionary relationships. It would even not be inconceivable to find mainland lineages to group closely with the western island taxa, if little genetic drift had occurred in the initial population. nonetheless, the divergence of this species' lineages seems to have taken place too recently to award them species status, as compared to the level of genetic divergence at which clades are usually considered distinct species.
N. c. limnaeetus appears for all that can be said with reasonable certainty basal pool of lineages in the crestless group that, despite not being monophyletic, should be considered a valid taxon as long as gene flow is possible through its range. In addition, as ancient DNA from museum specimens was used extensively, the possibility of ghost lineages must be considered. If it is assumed that all or most of the ancient lineages still exist today, considerable recombination must have taken place as the two genes' phylogenies do not agree much, indicating a healthy level of gene flow. Whether this still holds true today remains to be determined.
Black-winged Kite (Elanus Caeruleus)
The black-winged kite (Elanus caeruleus) is a small diurnal bird of prey in the family Accipitridae best known for its habit of hovering over open grasslands in the manner of the much smaller kestrels. This Eurasian and African species was sometimes combined with the Australian black-shouldered kite (Elanus axillaris) and the white-tailed kite (Elanus leucurus) of North and South America which together form a superspecies. This kite is distinctive, with long-wings, white, grey and black plumage and owl like forward-facing eyes with red irises.
Although mainly seen on the plains, they are sometimes seen on grassy slopes of hills in the higher elevation regions of Asia. They are not migratory, but make short-distance movements in response to weather.
Description
This long-winged raptor is predominantly grey or white with black shoulder patches, wing tips and eye stripe. The long falcon-like wings extend beyond the tail when the bird is perched. In flight, the short and square tail is visible and it is not forked as in the typical kites of the genus Milvus. When perched, often on roadside wires, it often adjusts its wings and jerks its tail up and down as if to balance itself.
The sexes are alike in plumage. Their large forward-facing eyes and velvety plumage are characters that are shared with owls and the genus itself has been considered as a basal group within the Accipitridae.
Distribution and habitat
The black-winged kite is a species primarily of open land and semi-deserts in sub-Saharan Africa and tropical Asia, but it has a foothold within Europe in Spain and Portugal. The species range appears to be expanding in southern Europe and possible in West Asia.
Several geographic populations have been named as subspecies and these include the nominate subspecies which occurs in Spain, Africa and Arabia. The subspecies vociferus is found east of this range across South Asia and into Southeast Asia. Along Sumatra, Java, Borneo and the Philippines subspecies hypoleucus (sometimes considered a full species) is found while wahgiensis is restricted to New Guinea. Subspecies sumatranus is not always recognized. The white-tailed kite and the black-shouldered kite were formerly included with this species but have since been treated as separate species.
Although found mainly on the plains they have been seen at higher altitudes in Sikkim (3,650 m (11,980 ft)),[9] the Nilgiris (Doddabetta, 2,670 m (8,760 ft)) and Nagaland (2,020 m (6,630 ft)).
They are said to be winter visitors in some parts of their range such as the Western Ghats.
Behaviour and ecology
The black-winged kite breeds at different times of the year across its range. Although nesting has been noted throughout the year in India, they appear not to breed in April and May. Courtship is noisy and involves chases and once the pair is formed they copulate frequently. The nest is a loose platform of twigs in which 3 or 4 eggs are laid. The female spends more effort in the construction of the nest than the male. The eggs are pale creamy with spots of deep red. Both parents incubate but when the chicks hatch, the male spends more time on foraging for food. Females initially feed the young, sometimes hunting close to the nest but will also receive food from the male. After fledging the young birds continue to be dependent for food on the male parent for about 80 days, initially transferring food at perch and later in the air.
The prey include grasshoppers, crickets and other large insects, lizards and rodents. Injured birds, small snakes and frogs have also been recorded. The slow hunting flight is like a harrier, but it will hover like a Kestrel. It has on rare occasions been known to hunt prey in flight. Favourite perches are used for hunting and for feeding but large prey may sometimes be handled on the ground.[15] In southern Africa, they appear to favour roadside verges for foraging and are sometimes killed by collisions with vehicles.
These birds roost communally with groups of 15 to 35 (larger numbers in Europe) converging at a large leafy tree. They are extremely silent and the calls recorded include a high-pitched squeal or a soft whistle. They call a lot mainly during the breeding season.
A species of nematode, Physaloptera acuticauda, has been recorded as a parasite of the species in South Africa.
[Credit: en.wikipedia.org]
After spending time with captive elephants it is hard not to advocate for their needs. The recent action of the Ringling Brothers is definitely pertinent to our current world. This female Asian elephant is a healthy animal, she would be more than capable of caring for herself, instead she is forced into relying on us. This life of confinement leaves her living in a series of concrete cells with daily access to a small courtyard. Downtime is spent in leg shackles. The stress is easily seen in her eyes. Canon A-1 50mm Kodak Tri-X 400.
Fish, any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes. Most fish species are cold-blooded; however, one species, the opah (Lampris guttatus), is warm-blooded.
The term fish is applied to a variety of vertebrates of several evolutionary lines. It describes a life-form rather than a taxonomic group. As members of the phylum Chordata, fish share certain features with other vertebrates. These features are gill slits at some point in the life cycle, a notochord, or skeletal supporting rod, a dorsal hollow nerve cord, and a tail. Living fishes represent some five classes, which are as distinct from one another as are the four classes of familiar air-breathing animals—amphibians, reptiles, birds, and mammals. For example, the jawless fishes (Agnatha) have gills in pouches and lack limb girdles. Extant agnathans are the lampreys and the hagfishes. As the name implies, the skeletons of fishes of the class Chondrichthyes (from chondr, “cartilage,” and ichthyes, “fish”) are made entirely of cartilage. Modern fish of this class lack a swim bladder, and their scales and teeth are made up of the same placoid material. Sharks, skates, and rays are examples of cartilaginous fishes. The bony fishes are by far the largest class. Examples range from the tiny seahorse to the 450-kg (1,000-pound) blue marlin, from the flattened soles and flounders to the boxy puffers and ocean sunfishes. Unlike the scales of the cartilaginous fishes, those of bony fishes, when present, grow throughout life and are made up of thin overlapping plates of bone. Bony fishes also have an operculum that covers the gill slits.
The study of fishes, the science of ichthyology, is of broad importance. Fishes are of interest to humans for many reasons, the most important being their relationship with and dependence on the environment. A more obvious reason for interest in fishes is their role as a moderate but important part of the world’s food supply. This resource, once thought unlimited, is now realized to be finite and in delicate balance with the biological, chemical, and physical factors of the aquatic environment. Overfishing, pollution, and alteration of the environment are the chief enemies of proper fisheries management, both in fresh waters and in the ocean. (For a detailed discussion of the technology and economics of fisheries, see commercial fishing.) Another practical reason for studying fishes is their use in disease control. As predators on mosquito larvae, they help curb malaria and other mosquito-borne diseases.
Fishes are valuable laboratory animals in many aspects of medical and biological research. For example, the readiness of many fishes to acclimate to captivity has allowed biologists to study behaviour, physiology, and even ecology under relatively natural conditions. Fishes have been especially important in the study of animal behaviour, where research on fishes has provided a broad base for the understanding of the more flexible behaviour of the higher vertebrates. The zebra fish is used as a model in studies of gene expression.
There are aesthetic and recreational reasons for an interest in fishes. Millions of people keep live fishes in home aquariums for the simple pleasure of observing the beauty and behaviour of animals otherwise unfamiliar to them. Aquarium fishes provide a personal challenge to many aquarists, allowing them to test their ability to keep a small section of the natural environment in their homes. Sportfishing is another way of enjoying the natural environment, also indulged in by millions of people every year. Interest in aquarium fishes and sportfishing supports multimillion-dollar industries throughout the world.
Fishes have been in existence for more than 450 million years, during which time they have evolved repeatedly to fit into almost every conceivable type of aquatic habitat. In a sense, land vertebrates are simply highly modified fishes: when fishes colonized the land habitat, they became tetrapod (four-legged) land vertebrates. The popular conception of a fish as a slippery, streamlined aquatic animal that possesses fins and breathes by gills applies to many fishes, but far more fishes deviate from that conception than conform to it. For example, the body is elongate in many forms and greatly shortened in others; the body is flattened in some (principally in bottom-dwelling fishes) and laterally compressed in many others; the fins may be elaborately extended, forming intricate shapes, or they may be reduced or even lost; and the positions of the mouth, eyes, nostrils, and gill openings vary widely. Air breathers have appeared in several evolutionary lines.
Many fishes are cryptically coloured and shaped, closely matching their respective environments; others are among the most brilliantly coloured of all organisms, with a wide range of hues, often of striking intensity, on a single individual. The brilliance of pigments may be enhanced by the surface structure of the fish, so that it almost seems to glow. A number of unrelated fishes have actual light-producing organs. Many fishes are able to alter their coloration—some for the purpose of camouflage, others for the enhancement of behavioral signals.
Fishes range in adult length from less than 10 mm (0.4 inch) to more than 20 metres (60 feet) and in weight from about 1.5 grams (less than 0.06 ounce) to many thousands of kilograms. Some live in shallow thermal springs at temperatures slightly above 42 °C (100 °F), others in cold Arctic seas a few degrees below 0 °C (32 °F) or in cold deep waters more than 4,000 metres (13,100 feet) beneath the ocean surface. The structural and, especially, the physiological adaptations for life at such extremes are relatively poorly known and provide the scientifically curious with great incentive for study.
Almost all natural bodies of water bear fish life, the exceptions being very hot thermal ponds and extremely salt-alkaline lakes, such as the Dead Sea in Asia and the Great Salt Lake in North America. The present distribution of fishes is a result of the geological history and development of Earth as well as the ability of fishes to undergo evolutionary change and to adapt to the available habitats. Fishes may be seen to be distributed according to habitat and according to geographical area. Major habitat differences are marine and freshwater. For the most part, the fishes in a marine habitat differ from those in a freshwater habitat, even in adjacent areas, but some, such as the salmon, migrate from one to the other. The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each other, both in obvious gross structure and in physiological attributes. Even in closely adjacent habitats where, for example, a tropical mountain torrent enters a lowland stream, the fish fauna will differ. The marine habitats can be divided into deep ocean floors (benthic), mid-water oceanic (bathypelagic), surface oceanic (pelagic), rocky coast, sandy coast, muddy shores, bays, estuaries, and others. Also, for example, rocky coastal shores in tropical and temperate regions will have different fish faunas, even when such habitats occur along the same coastline.
Although much is known about the present geographical distribution of fishes, far less is known about how that distribution came about. Many parts of the fish fauna of the fresh waters of North America and Eurasia are related and undoubtedly have a common origin. The faunas of Africa and South America are related, extremely old, and probably an expression of the drifting apart of the two continents. The fauna of southern Asia is related to that of Central Asia, and some of it appears to have entered Africa. The extremely large shore-fish faunas of the Indian and tropical Pacific oceans comprise a related complex, but the tropical shore fauna of the Atlantic, although containing Indo-Pacific components, is relatively limited and probably younger. The Arctic and Antarctic marine faunas are quite different from each other. The shore fauna of the North Pacific is quite distinct, and that of the North Atlantic more limited and probably younger. Pelagic oceanic fishes, especially those in deep waters, are similar the world over, showing little geographical isolation in terms of family groups. The deep oceanic habitat is very much the same throughout the world, but species differences do exist, showing geographical areas determined by oceanic currents and water masses.
All aspects of the life of a fish are closely correlated with adaptation to the total environment, physical, chemical, and biological. In studies, all the interdependent aspects of fish, such as behaviour, locomotion, reproduction, and physical and physiological characteristics, must be taken into account.
Correlated with their adaptation to an extremely wide variety of habitats is the extremely wide variety of life cycles that fishes display. The great majority hatch from relatively small eggs a few days to several weeks or more after the eggs are scattered in the water. Newly hatched young are still partially undeveloped and are called larvae until body structures such as fins, skeleton, and some organs are fully formed. Larval life is often very short, usually less than a few weeks, but it can be very long, some lampreys continuing as larvae for at least five years. Young and larval fishes, before reaching sexual maturity, must grow considerably, and their small size and other factors often dictate that they live in a habitat different than that of the adults. For example, most tropical marine shore fishes have pelagic larvae. Larval food also is different, and larval fishes often live in shallow waters, where they may be less exposed to predators.
After a fish reaches adult size, the length of its life is subject to many factors, such as innate rates of aging, predation pressure, and the nature of the local climate. The longevity of a species in the protected environment of an aquarium may have nothing to do with how long members of that species live in the wild. Many small fishes live only one to three years at the most. In some species, however, individuals may live as long as 10 or 20 or even 100 years.
Fish behaviour is a complicated and varied subject. As in almost all animals with a central nervous system, the nature of a response of an individual fish to stimuli from its environment depends upon the inherited characteristics of its nervous system, on what it has learned from past experience, and on the nature of the stimuli. Compared with the variety of human responses, however, that of a fish is stereotyped, not subject to much modification by “thought” or learning, and investigators must guard against anthropomorphic interpretations of fish behaviour.
Fishes perceive the world around them by the usual senses of sight, smell, hearing, touch, and taste and by special lateral line water-current detectors. In the few fishes that generate electric fields, a process that might best be called electrolocation aids in perception. One or another of these senses often is emphasized at the expense of others, depending upon the fish’s other adaptations. In fishes with large eyes, the sense of smell may be reduced; others, with small eyes, hunt and feed primarily by smell (such as some eels).
Specialized behaviour is primarily concerned with the three most important activities in the fish’s life: feeding, reproduction, and escape from enemies. Schooling behaviour of sardines on the high seas, for instance, is largely a protective device to avoid enemies, but it is also associated with and modified by their breeding and feeding requirements. Predatory fishes are often solitary, lying in wait to dart suddenly after their prey, a kind of locomotion impossible for beaked parrot fishes, which feed on coral, swimming in small groups from one coral head to the next. In addition, some predatory fishes that inhabit pelagic environments, such as tunas, often school.
Sleep in fishes, all of which lack true eyelids, consists of a seemingly listless state in which the fish maintains its balance but moves slowly. If attacked or disturbed, most can dart away. A few kinds of fishes lie on the bottom to sleep. Most catfishes, some loaches, and some eels and electric fishes are strictly nocturnal, being active and hunting for food during the night and retiring during the day to holes, thick vegetation, or other protective parts of the environment.
Communication between members of a species or between members of two or more species often is extremely important, especially in breeding behaviour (see below Reproduction). The mode of communication may be visual, as between the small so-called cleaner fish and a large fish of a very different species. The larger fish often allows the cleaner to enter its mouth to remove gill parasites. The cleaner is recognized by its distinctive colour and actions and therefore is not eaten, even if the larger fish is normally a predator. Communication is often chemical, signals being sent by specific chemicals called pheromones.
Many fishes have a streamlined body and swim freely in open water. Fish locomotion is closely correlated with habitat and ecological niche (the general position of the animal to its environment).
Many fishes in both marine and fresh waters swim at the surface and have mouths adapted to feed best (and sometimes only) at the surface. Often such fishes are long and slender, able to dart at surface insects or at other surface fishes and in turn to dart away from predators; needlefishes, halfbeaks, and topminnows (such as killifish and mosquito fish) are good examples. Oceanic flying fishes escape their predators by gathering speed above the water surface, with the lower lobe of the tail providing thrust in the water. They then glide hundreds of yards on enlarged, winglike pectoral and pelvic fins. South American freshwater flying fishes escape their enemies by jumping and propelling their strongly keeled bodies out of the water.
So-called mid-water swimmers, the most common type of fish, are of many kinds and live in many habitats. The powerful fusiform tunas and the trouts, for example, are adapted for strong, fast swimming, the tunas to capture prey speedily in the open ocean and the trouts to cope with the swift currents of streams and rivers. The trout body form is well adapted to many habitats. Fishes that live in relatively quiet waters such as bays or lake shores or slow rivers usually are not strong, fast swimmers but are capable of short, quick bursts of speed to escape a predator. Many of these fishes have their sides flattened, examples being the sunfish and the freshwater angelfish of aquarists. Fish associated with the bottom or substrate usually are slow swimmers. Open-water plankton-feeding fishes almost always remain fusiform and are capable of rapid, strong movement (for example, sardines and herrings of the open ocean and also many small minnows of streams and lakes).
Bottom-living fishes are of many kinds and have undergone many types of modification of their body shape and swimming habits. Rays, which evolved from strong-swimming mid-water sharks, usually stay close to the bottom and move by undulating their large pectoral fins. Flounders live in a similar habitat and move over the bottom by undulating the entire body. Many bottom fishes dart from place to place, resting on the bottom between movements, a motion common in gobies. One goby relative, the mudskipper, has taken to living at the edge of pools along the shore of muddy mangrove swamps. It escapes its enemies by flipping rapidly over the mud, out of the water. Some catfishes, synbranchid eels, the so-called climbing perch, and a few other fishes venture out over damp ground to find more promising waters than those that they left. They move by wriggling their bodies, sometimes using strong pectoral fins; most have accessory air-breathing organs. Many bottom-dwelling fishes live in mud holes or rocky crevices. Marine eels and gobies commonly are found in such habitats and for the most part venture far beyond their cavelike homes. Some bottom dwellers, such as the clingfishes (Gobiesocidae), have developed powerful adhesive disks that enable them to remain in place on the substrate in areas such as rocky coasts, where the action of the waves is great.
The methods of reproduction in fishes are varied, but most fishes lay a large number of small eggs, fertilized and scattered outside of the body. The eggs of pelagic fishes usually remain suspended in the open water. Many shore and freshwater fishes lay eggs on the bottom or among plants. Some have adhesive eggs. The mortality of the young and especially of the eggs is very high, and often only a few individuals grow to maturity out of hundreds, thousands, and in some cases millions of eggs laid.
Males produce sperm, usually as a milky white substance called milt, in two (sometimes one) testes within the body cavity. In bony fishes a sperm duct leads from each testis to a urogenital opening behind the vent or anus. In sharks and rays and in cyclostomes the duct leads to a cloaca. Sometimes the pelvic fins are modified to help transmit the milt to the eggs at the female’s vent or on the substrate where the female has placed them. Sometimes accessory organs are used to fertilize females internally—for example, the claspers of many sharks and rays.
In the females the eggs are formed in two ovaries (sometimes only one) and pass through the ovaries to the urogenital opening and to the outside. In some fishes the eggs are fertilized internally but are shed before development takes place. Members of about a dozen families each of bony fishes (teleosts) and sharks bear live young. Many skates and rays also bear live young. In some bony fishes the eggs simply develop within the female, the young emerging when the eggs hatch (ovoviviparous). Others develop within the ovary and are nourished by ovarian tissues after hatching (viviparous). There are also other methods utilized by fishes to nourish young within the female. In all live-bearers the young are born at a relatively large size and are few in number. In one family of primarily marine fishes, the surfperches from the Pacific coast of North America, Japan, and Korea, the males of at least one species are born sexually mature, although they are not fully grown.
Some fishes are hermaphroditic—an individual producing both sperm and eggs, usually at different stages of its life. Self-fertilization, however, is probably rare.
Successful reproduction and, in many cases, defense of the eggs and the young are assured by rather stereotypical but often elaborate courtship and parental behaviour, either by the male or the female or both. Some fishes prepare nests by hollowing out depressions in the sand bottom (cichlids, for example), build nests with plant materials and sticky threads excreted by the kidneys (sticklebacks), or blow a cluster of mucus-covered bubbles at the water surface (gouramis). The eggs are laid in these structures. Some varieties of cichlids and catfishes incubate eggs in their mouths.
Some fishes, such as salmon, undergo long migrations from the ocean and up large rivers to spawn in the gravel beds where they themselves hatched (anadromous fishes). Some, such as the freshwater eels (family Anguillidae), live and grow to maturity in fresh water and migrate to the sea to spawn (catadromous fishes). Other fishes undertake shorter migrations from lakes into streams, within the ocean, or enter spawning habitats that they do not ordinarily occupy in other ways.
The basic structure and function of the fish body are similar to those of all other vertebrates. The usual four types of tissues are present: surface or epithelial, connective (bone, cartilage, and fibrous tissues, as well as their derivative, blood), nerve, and muscle tissues. In addition, the fish’s organs and organ systems parallel those of other vertebrates.
The typical fish body is streamlined and spindle-shaped, with an anterior head, a gill apparatus, and a heart, the latter lying in the midline just below the gill chamber. The body cavity, containing the vital organs, is situated behind the head in the lower anterior part of the body. The anus usually marks the posterior termination of the body cavity and most often occurs just in front of the base of the anal fin. The spinal cord and vertebral column continue from the posterior part of the head to the base of the tail fin, passing dorsal to the body cavity and through the caudal (tail) region behind the body cavity. Most of the body is of muscular tissue, a high proportion of which is necessitated by swimming. In the course of evolution this basic body plan has been modified repeatedly into the many varieties of fish shapes that exist today.
The skeleton forms an integral part of the fish’s locomotion system, as well as serving to protect vital parts. The internal skeleton consists of the skull bones (except for the roofing bones of the head, which are really part of the external skeleton), the vertebral column, and the fin supports (fin rays). The fin supports are derived from the external skeleton but will be treated here because of their close functional relationship to the internal skeleton. The internal skeleton of cyclostomes, sharks, and rays is of cartilage; that of many fossil groups and some primitive living fishes is mostly of cartilage but may include some bone. In place of the vertebral column, the earliest vertebrates had a fully developed notochord, a flexible stiff rod of viscous cells surrounded by a strong fibrous sheath. During the evolution of modern fishes the rod was replaced in part by cartilage and then by ossified cartilage. Sharks and rays retain a cartilaginous vertebral column; bony fishes have spool-shaped vertebrae that in the more primitive living forms only partially replace the notochord. The skull, including the gill arches and jaws of bony fishes, is fully, or at least partially, ossified. That of sharks and rays remains cartilaginous, at times partially replaced by calcium deposits but never by true bone.
The supportive elements of the fins (basal or radial bones or both) have changed greatly during fish evolution. Some of these changes are described in the section below (Evolution and paleontology). Most fishes possess a single dorsal fin on the midline of the back. Many have two and a few have three dorsal fins. The other fins are the single tail and anal fins and paired pelvic and pectoral fins. A small fin, the adipose fin, with hairlike fin rays, occurs in many of the relatively primitive teleosts (such as trout) on the back near the base of the caudal fin.
The skin of a fish must serve many functions. It aids in maintaining the osmotic balance, provides physical protection for the body, is the site of coloration, contains sensory receptors, and, in some fishes, functions in respiration. Mucous glands, which aid in maintaining the water balance and offer protection from bacteria, are extremely numerous in fish skin, especially in cyclostomes and teleosts. Since mucous glands are present in the modern lampreys, it is reasonable to assume that they were present in primitive fishes, such as the ancient Silurian and Devonian agnathans. Protection from abrasion and predation is another function of the fish skin, and dermal (skin) bone arose early in fish evolution in response to this need. It is thought that bone first evolved in skin and only later invaded the cartilaginous areas of the fish’s body, to provide additional support and protection. There is some argument as to which came first, cartilage or bone, and fossil evidence does not settle the question. In any event, dermal bone has played an important part in fish evolution and has different characteristics in different groups of fishes. Several groups are characterized at least in part by the kind of bony scales they possess.
Scales have played an important part in the evolution of fishes. Primitive fishes usually had thick bony plates or thick scales in several layers of bone, enamel, and related substances. Modern teleost fishes have scales of bone, which, while still protective, allow much more freedom of motion in the body. A few modern teleosts (some catfishes, sticklebacks, and others) have secondarily acquired bony plates in the skin. Modern and early sharks possessed placoid scales, a relatively primitive type of scale with a toothlike structure, consisting of an outside layer of enamel-like substance (vitrodentine), an inner layer of dentine, and a pulp cavity containing nerves and blood vessels. Primitive bony fishes had thick scales of either the ganoid or the cosmoid type. Cosmoid scales have a hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine). In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges), lack enameloid and dentine layers.
Skin has several other functions in fishes. It is well supplied with nerve endings and presumably receives tactile, thermal, and pain stimuli. Skin is also well supplied with blood vessels. Some fishes breathe in part through the skin, by the exchange of oxygen and carbon dioxide between the surrounding water and numerous small blood vessels near the skin surface.
Skin serves as protection through the control of coloration. Fishes exhibit an almost limitless range of colours. The colours often blend closely with the surroundings, effectively hiding the animal. Many fishes use bright colours for territorial advertisement or as recognition marks for other members of their own species, or sometimes for members of other species. Many fishes can change their colour to a greater or lesser degree, by movement of pigment within the pigment cells (chromatophores). Black pigment cells (melanophores), of almost universal occurrence in fishes, are often juxtaposed with other pigment cells. When placed beneath iridocytes or leucophores (bearing the silvery or white pigment guanine), melanophores produce structural colours of blue and green. These colours are often extremely intense, because they are formed by refraction of light through the needlelike crystals of guanine. The blue and green refracted colours are often relatively pure, lacking the red and yellow rays, which have been absorbed by the black pigment (melanin) of the melanophores. Yellow, orange, and red colours are produced by erythrophores, cells containing the appropriate carotenoid pigments. Other colours are produced by combinations of melanophores, erythrophores, and iridocytes.
The major portion of the body of most fishes consists of muscles. Most of the mass is trunk musculature, the fin muscles usually being relatively small. The caudal fin is usually the most powerful fin, being moved by the trunk musculature. The body musculature is usually arranged in rows of chevron-shaped segments on each side. Contractions of these segments, each attached to adjacent vertebrae and vertebral processes, bends the body on the vertebral joint, producing successive undulations of the body, passing from the head to the tail, and producing driving strokes of the tail. It is the latter that provides the strong forward movement for most fishes.
The digestive system, in a functional sense, starts at the mouth, with the teeth used to capture prey or collect plant foods. Mouth shape and tooth structure vary greatly in fishes, depending on the kind of food normally eaten. Most fishes are predacious, feeding on small invertebrates or other fishes and have simple conical teeth on the jaws, on at least some of the bones of the roof of the mouth, and on special gill arch structures just in front of the esophagus. The latter are throat teeth. Most predacious fishes swallow their prey whole, and the teeth are used for grasping and holding prey, for orienting prey to be swallowed (head first) and for working the prey toward the esophagus. There are a variety of tooth types in fishes. Some fishes, such as sharks and piranhas, have cutting teeth for biting chunks out of their victims. A shark’s tooth, although superficially like that of a piranha, appears in many respects to be a modified scale, while that of the piranha is like that of other bony fishes, consisting of dentine and enamel. Parrot fishes have beaklike mouths with short incisor-like teeth for breaking off coral and have heavy pavementlike throat teeth for crushing the coral. Some catfishes have small brushlike teeth, arranged in rows on the jaws, for scraping plant and animal growth from rocks. Many fishes (such as the Cyprinidae or minnows) have no jaw teeth at all but have very strong throat teeth.
Some fishes gather planktonic food by straining it from their gill cavities with numerous elongate stiff rods (gill rakers) anchored by one end to the gill bars. The food collected on these rods is passed to the throat, where it is swallowed. Most fishes have only short gill rakers that help keep food particles from escaping out the mouth cavity into the gill chamber.
Once reaching the throat, food enters a short, often greatly distensible esophagus, a simple tube with a muscular wall leading into a stomach. The stomach varies greatly in fishes, depending upon the diet. In most predacious fishes it is a simple straight or curved tube or pouch with a muscular wall and a glandular lining. Food is largely digested there and leaves the stomach in liquid form.
Between the stomach and the intestine, ducts enter the digestive tube from the liver and pancreas. The liver is a large, clearly defined organ. The pancreas may be embedded in it, diffused through it, or broken into small parts spread along some of the intestine. The junction between the stomach and the intestine is marked by a muscular valve. Pyloric ceca (blind sacs) occur in some fishes at this junction and have a digestive or absorptive function or both.
The intestine itself is quite variable in length, depending upon the fish’s diet. It is short in predacious forms, sometimes no longer than the body cavity, but long in herbivorous forms, being coiled and several times longer than the entire length of the fish in some species of South American catfishes. The intestine is primarily an organ for absorbing nutrients into the bloodstream. The larger its internal surface, the greater its absorptive efficiency, and a spiral valve is one method of increasing its absorption surface.
Sharks, rays, chimaeras, lungfishes, surviving chondrosteans, holosteans, and even a few of the more primitive teleosts have a spiral valve or at least traces of it in the intestine. Most modern teleosts have increased the area of the intestinal walls by having numerous folds and villi (fingerlike projections) somewhat like those in humans. Undigested substances are passed to the exterior through the anus in most teleost fishes. In lungfishes, sharks, and rays, it is first passed through the cloaca, a common cavity receiving the intestinal opening and the ducts from the urogenital system.
Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through the mouth passes backward between the gill bars and over the gill filaments, where the exchange of gases takes place. The gills are protected by a gill cover in teleosts and many other fishes but by flaps of skin in sharks, rays, and some of the older fossil fish groups. The blood capillaries in the gill filaments are close to the gill surface to take up oxygen from the water and to give up excess carbon dioxide to the water.
Most modern fishes have a hydrostatic (ballast) organ, called the swim bladder, that lies in the body cavity just below the kidney and above the stomach and intestine. It originated as a diverticulum of the digestive canal. In advanced teleosts, especially the acanthopterygians, the bladder has lost its connection with the digestive tract, a condition called physoclistic. The connection has been retained (physostomous) by many relatively primitive teleosts. In several unrelated lines of fishes, the bladder has become specialized as a lung or, at least, as a highly vascularized accessory breathing organ. Some fishes with such accessory organs are obligate air breathers and will drown if denied access to the surface, even in well-oxygenated water. Fishes with a hydrostatic form of swim bladder can control their depth by regulating the amount of gas in the bladder. The gas, mostly oxygen, is secreted into the bladder by special glands, rendering the fish more buoyant; the gas is absorbed into the bloodstream by another special organ, reducing the overall buoyancy and allowing the fish to sink. Some deep-sea fishes may have oils, rather than gas, in the bladder. Other deep-sea and some bottom-living forms have much-reduced swim bladders or have lost the organ entirely.
The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in primitive fishes. More or less intermediate forms still survive among the more primitive types of fishes, such as the lungfishes Lepidosiren and Protopterus.
The circulatory, or blood vascular, system consists of the heart, the arteries, the capillaries, and the veins. It is in the capillaries that the interchange of oxygen, carbon dioxide, nutrients, and other substances such as hormones and waste products takes place. The capillaries lead to the veins, which return the venous blood with its waste products to the heart, kidneys, and gills. There are two kinds of capillary beds: those in the gills and those in the rest of the body. The heart, a folded continuous muscular tube with three or four saclike enlargements, undergoes rhythmic contractions and receives venous blood in a sinus venosus. It passes the blood to an auricle and then into a thick muscular pump, the ventricle. From the ventricle the blood goes to a bulbous structure at the base of a ventral aorta just below the gills. The blood passes to the afferent (receiving) arteries of the gill arches and then to the gill capillaries. There waste gases are given off to the environment, and oxygen is absorbed. The oxygenated blood enters efferent (exuant) arteries of the gill arches and then flows into the dorsal aorta. From there blood is distributed to the tissues and organs of the body. One-way valves prevent backflow. The circulation of fishes thus differs from that of the reptiles, birds, and mammals in that oxygenated blood is not returned to the heart prior to distribution to the other parts of the body.
The primary excretory organ in fishes, as in other vertebrates, is the kidney. In fishes some excretion also takes place in the digestive tract, skin, and especially the gills (where ammonia is given off). Compared with land vertebrates, fishes have a special problem in maintaining their internal environment at a constant concentration of water and dissolved substances, such as salts. Proper balance of the internal environment (homeostasis) of a fish is in a great part maintained by the excretory system, especially the kidney.
The kidney, gills, and skin play an important role in maintaining a fish’s internal environment and checking the effects of osmosis. Marine fishes live in an environment in which the water around them has a greater concentration of salts than they can have inside their body and still maintain life. Freshwater fishes, on the other hand, live in water with a much lower concentration of salts than they require inside their bodies. Osmosis tends to promote the loss of water from the body of a marine fish and absorption of water by that of a freshwater fish. Mucus in the skin tends to slow the process but is not a sufficient barrier to prevent the movement of fluids through the permeable skin. When solutions on two sides of a permeable membrane have different concentrations of dissolved substances, water will pass through the membrane into the more concentrated solution, while the dissolved chemicals move into the area of lower concentration (diffusion).
The kidney of freshwater fishes is often larger in relation to body weight than that of marine fishes. In both groups the kidney excretes wastes from the body, but the kidney of freshwater fishes also excretes large amounts of water, counteracting the water absorbed through the skin. Freshwater fishes tend to lose salt to the environment and must replace it. They get some salt from their food, but the gills and skin inside the mouth actively absorb salt from water passed through the mouth. This absorption is performed by special cells capable of moving salts against the diffusion gradient. Freshwater fishes drink very little water and take in little water with their food.
Marine fishes must conserve water, and therefore their kidneys excrete little water. To maintain their water balance, marine fishes drink large quantities of seawater, retaining most of the water and excreting the salt. Most nitrogenous waste in marine fishes appears to be secreted by the gills as ammonia. Marine fishes can excrete salt by clusters of special cells (chloride cells) in the gills.
There are several teleosts—for example, the salmon—that travel between fresh water and seawater and must adjust to the reversal of osmotic gradients. They adjust their physiological processes by spending time (often surprisingly little time) in the intermediate brackish environment.
Marine hagfishes, sharks, and rays have osmotic concentrations in their blood about equal to that of seawater and so do not have to drink water nor perform much physiological work to maintain their osmotic balance. In sharks and rays the osmotic concentration is kept high by retention of urea in the blood. Freshwater sharks have a lowered concentration of urea in the blood.
Endocrine glands secrete their products into the bloodstream and body tissues and, along with the central nervous system, control and regulate many kinds of body functions. Cyclostomes have a well-developed endocrine system, and presumably it was well developed in the early Agnatha, ancestral to modern fishes. Although the endocrine system in fishes is similar to that of higher vertebrates, there are numerous differences in detail. The pituitary, the thyroid, the suprarenals, the adrenals, the pancreatic islets, the sex glands (ovaries and testes), the inner wall of the intestine, and the bodies of the ultimobranchial gland make up the endocrine system in fishes. There are some others whose function is not well understood. These organs regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour. Many of these activities are also controlled in part by the central nervous system, which works with the endocrine system in maintaining the life of a fish. Some parts of the endocrine system are developmentally, and undoubtedly evolutionarily, derived from the nervous system.
As in all vertebrates, the nervous system of fishes is the primary mechanism coordinating body activities, as well as integrating these activities in the appropriate manner with stimuli from the environment. The central nervous system, consisting of the brain and spinal cord, is the primary integrating mechanism. The peripheral nervous system, consisting of nerves that connect the brain and spinal cord to various body organs, carries sensory information from special receptor organs such as the eyes, internal ears, nares (sense of smell), taste glands, and others to the integrating centres of the brain and spinal cord. The peripheral nervous system also carries information via different nerve cells from the integrating centres of the brain and spinal cord. This coded information is carried to the various organs and body systems, such as the skeletal muscular system, for appropriate action in response to the original external or internal stimulus. Another branch of the nervous system, the autonomic nervous system, helps to coordinate the activities of many glands and organs and is itself closely connected to the integrating centres of the brain.
The brain of the fish is divided into several anatomical and functional parts, all closely interconnected but each serving as the primary centre of integrating particular kinds of responses and activities. Several of these centres or parts are primarily associated with one type of sensory perception, such as sight, hearing, or smell (olfaction).
The sense of smell is important in almost all fishes. Certain eels with tiny eyes depend mostly on smell for location of food. The olfactory, or nasal, organ of fishes is located on the dorsal surface of the snout. The lining of the nasal organ has special sensory cells that perceive chemicals dissolved in the water, such as substances from food material, and send sensory information to the brain by way of the first cranial nerve. Odour also serves as an alarm system. Many fishes, especially various species of freshwater minnows, react with alarm to a chemical released from the skin of an injured member of their own species.
Many fishes have a well-developed sense of taste, and tiny pitlike taste buds or organs are located not only within their mouth cavities but also over their heads and parts of their body. Catfishes, which often have poor vision, have barbels (“whiskers”) that serve as supplementary taste organs, those around the mouth being actively used to search out food on the bottom. Some species of naturally blind cave fishes are especially well supplied with taste buds, which often cover most of their body surface.
Sight is extremely important in most fishes. The eye of a fish is basically like that of all other vertebrates, but the eyes of fishes are extremely varied in structure and adaptation. In general, fishes living in dark and dim water habitats have large eyes, unless they have specialized in some compensatory way so that another sense (such as smell) is dominant, in which case the eyes will often be reduced. Fishes living in brightly lighted shallow waters often will have relatively small but efficient eyes. Cyclostomes have somewhat less elaborate eyes than other fishes, with skin stretched over the eyeball perhaps making their vision somewhat less effective. Most fishes have a spherical lens and accommodate their vision to far or near subjects by moving the lens within the eyeball. A few sharks accommodate by changing the shape of the lens, as in land vertebrates. Those fishes that are heavily dependent upon the eyes have especially strong muscles for accommodation. Most fishes see well, despite the restrictions imposed by frequent turbidity of the water and by light refraction.
Fossil evidence suggests that colour vision evolved in fishes more than 300 million years ago, but not all living fishes have retained this ability. Experimental evidence indicates that many shallow-water fishes, if not all, have colour vision and see some colours especially well, but some bottom-dwelling shore fishes live in areas where the water is sufficiently deep to filter out most if not all colours, and these fishes apparently never see colours. When tested in shallow water, they apparently are unable to respond to colour differences.
Sound perception and balance are intimately associated senses in a fish. The organs of hearing are entirely internal, located within the skull, on each side of the brain and somewhat behind the eyes. Sound waves, especially those of low frequencies, travel readily through water and impinge directly upon the bones and fluids of the head and body, to be transmitted to the hearing organs. Fishes readily respond to sound; for example, a trout conditioned to escape by the approach of fishermen will take flight upon perceiving footsteps on a stream bank even if it cannot see a fisherman. Compared with humans, however, the range of sound frequencies heard by fishes is greatly restricted. Many fishes communicate with each other by producing sounds in their swim bladders, in their throats by rasping their teeth, and in other ways.
A fish or other vertebrate seldom has to rely on a single type of sensory information to determine the nature of the environment around it. A catfish uses taste and touch when examining a food object with its oral barbels. Like most other animals, fishes have many touch receptors over their body surface. Pain and temperature receptors also are present in fishes and presumably produce the same kind of information to a fish as to humans. Fishes react in a negative fashion to stimuli that would be painful to human beings, suggesting that they feel a sensation of pain.
An important sensory system in fishes that is absent in other vertebrates (except some amphibians) is the lateral line system. This consists of a series of heavily innervated small canals located in the skin and bone around the eyes, along the lower jaw, over the head, and down the mid-side of the body, where it is associated with the scales. Intermittently along these canals are located tiny sensory organs (pit organs) that apparently detect changes in pressure. The system allows a fish to sense changes in water currents and pressure, thereby helping the fish to orient itself to the various changes that occur in the physical environment.
Although a great many fossil fishes have been found and described, they represent a tiny portion of the long and complex evolution of fishes, and knowledge of fish evolution remains relatively fragmentary. In the classification presented in this article, fishlike vertebrates are divided into seven categories, the members of each having a different basic structural organization and different physical and physiological adaptations for the problems presented by the environment. The broad basic pattern has been one of successive replacement of older groups by newer, better-adapted groups. One or a few members of a group evolved a basically more efficient means of feeding, breathing, or swimming or several better ways of living. These better-adapted groups then forced the extinction of members of the older group with which they competed for available food, breeding places, or other necessities of life. As the new fishes became well established, some of them evolved further and adapted to other habitats, where they continued to replace members of the old group already there. The process was repeated until all or almost all members of the old group in a variety of habitats had been replaced by members of the newer evolutionary line.
The earliest vertebrate fossils of certain relationships are fragments of dermal armour of jawless fishes (superclass Agnatha, order Heterostraci) from the Upper Ordovician Period in North America, about 450 million years in age. Early Ordovician toothlike fragments from the former Soviet Union are less certainly remains of agnathans. It is uncertain whether the North American jawless fishes inhabited shallow coastal marine waters, where their remains became fossilized, or were freshwater vertebrates washed into coastal deposits by stream action.
Jawless fishes probably arose from ancient, small, soft-bodied filter-feeding organisms much like and probably also ancestral to the modern sand-dwelling filter feeders, the Cephalochordata (Amphioxus and its relatives). The body in the ancestral animals was probably stiffened by a notochord. Although a vertebrate origin in fresh water is much debated by paleontologists, it is possible that mobility of the body and protection provided by dermal armour arose in response to streamflow in the freshwater environment and to the need to escape from and resist the clawed invertebrate eurypterids that lived in the same waters. Because of the marine distribution of the surviving primitive chordates, however, many paleontologists doubt that the vertebrates arose in fresh water.
Heterostracan remains are next found in what appear to be delta deposits in two North American localities of Silurian age. By the close of the Silurian, about 416 million years ago, European heterostracan remains are found in what appear to be delta or coastal deposits. In the Late Silurian of the Baltic area, lagoon or freshwater deposits yield jawless fishes of the order Osteostraci. Somewhat later in the Silurian from the same region, layers contain fragments of jawed acanthodians, the earliest group of jawed vertebrates, and of jawless fishes. These layers lie between marine beds but appear to be washed out from fresh waters of a coastal region.
It is evident, therefore, that by the end of the Silurian both jawed and jawless vertebrates were well established and already must have had a long history of development. Yet paleontologists have remains only of specialized forms that cannot have been the ancestors of the placoderms and bony fishes that appear in the next period, the Devonian. No fossils are known of the more primitive ancestors of the agnathans and acanthodians. The extensive marine beds of the Silurian and those of the Ordovician are essentially void of vertebrate history. It is believed that the ancestors of fishlike vertebrates evolved in upland fresh waters, where whatever few and relatively small fossil beds were made probably have been long since eroded away. Remains of the earliest vertebrates may never be found.
By the close of the Silurian, all known orders of jawless vertebrates had evolved, except perhaps the modern cyclostomes, which are without the hard parts that ordinarily are preserved as fossils. Cyclostomes were unknown as fossils until 1968, when a lamprey of modern body structure was reported from the Middle Pennsylvanian of Illinois, in deposits more than 300 million years old. Fossil evidence of the four orders of armoured jawless vertebrates is absent from deposits later than the Devonian. Presumably, these vertebrates became extinct at that time, being replaced by the more efficient and probably more aggressive placoderms, acanthodians, selachians (sharks and relatives), and by early bony fishes. Cyclostomes survived probably because early on they evolved from anaspid agnathans and developed a rasping tonguelike structure and a sucking mouth, enabling them to prey on other fishes. With this way of life they apparently had no competition from other fish groups. Cyclostomes, the hagfishes and lampreys, were once thought to be closely related because of the similarity in their suctorial mouths, but it is now understood that the hagfishes, order Myxiniformes, are the most primitive living chordates, and they are classified separately from the lampreys, order Petromyzontiformes.
Early jawless vertebrates probably fed on tiny organisms by filter feeding, as do the larvae of their descendants, the modern lampreys. The gill cavity of the early agnathans was large. It is thought that small organisms taken from the bottom by a nibbling action of the mouth, or more certainly by a sucking action through the mouth, were passed into the gill cavity along with water for breathing. Small organisms then were strained out by the gill apparatus and directed to the food canal. The gill apparatus thus evolved as a feeding, as well as a breathing, structure. The head and gills in the agnathans were protected by a heavy dermal armour; the tail region was free, allowing motion for swimming.
Most important for the evolution of fishes and vertebrates in general was the early appearance of bone, cartilage, and enamel-like substance. These materials became modified in later fishes, enabling them to adapt to many aquatic environments and finally even to land. Other basic organs and tissues of the vertebrates—such as the central nervous system, heart, liver, digestive tract, kidney, and circulatory system— undoubtedly were present in the ancestors of the agnathans. In many ways, bone, both external and internal, was the key to vertebrate evolution.
The next class of fishes to appear was the Acanthodii, containing the earliest known jawed vertebrates, which arose in the Late Silurian, more than 416 million years ago. The acanthodians declined after the Devonian but lasted into the Early Permian, a little less than 280 million years ago. The first complete specimens appear in Lower Devonian freshwater deposits, but later in the Devonian and Permian some members appear to have been marine. Most were small fishes, not more than 75 cm (approximately 30 inches) in length.
We know nothing of the ancestors of the acanthodians. They must have arisen from some jawless vertebrate, probably in fresh water. They appear to have been active swimmers with almost no head armour but with large eyes, indicating that they depended heavily on vision. Perhaps they preyed on invertebrates. The rows of spines and spinelike fins between the pectoral and pelvic fins give some credence to the idea that paired fins arose from “fin folds” along the body sides.
The relationships of the acanthodians to other jawed vertebrates are obscure. They possess features found in both sharks and bony fishes. They are like early bony fishes in possessing ganoidlike scales and a partially ossified internal skeleton. Certain aspects of the jaw appear to be more like those of bony fishes than sharks, but the bony fin spines and certain aspects of the gill apparatus would seem to favour relationships with early sharks. Acanthodians do not seem particularly close to the Placodermi, although, like the placoderms, they apparently possessed less efficient tooth replacement and tooth structure than the sharks and the bony fishes, possibly one reason for their subsequent extinction.
The tallest North American bird standing as much as 5 foot tall, the Whooping Crane is an endangered species that is still struggling to come back from near extinction. In 1941, there were as few as 15 Whooping Cranes remaining in the wild, with only two surviving in captivity. Thanks to conservation efforts, as of February 2015, the total population was 603 birds, which included 161 held in captivity. The four that I encountered on August 27, 2016 are some of the 440 Whooping Cranes that still remain in the wild.
I had been chasing Whooping Cranes to photograph since I first began seeing reports of them in eastern Missouri earlier this year. In May I was at Eagle Bluffs Conservation Area near Columbia, Missouri, photographing young eagles when I began to notice an unusual number of cars driving quickly through the conservation area towards one of the back lakes. Suspecting something was going on, I continued photographing the eagles hoping that whatever it was that the others were chasing, it would still be there by the time I made my way to the far end of the conservation area. Unfortunately, that wasn’t the case. By the time I arrived, everyone was getting back into their cars. Several people stopped me and told me that I had just missed four Whooping Cranes who had stopped for breakfast. They pointed in the direction of where the Whooping Cranes had flown, but I was unable to find any sign of them.
About 10 days ago (mid-August) I began seeing reports of four Whooping Cranes in Kaskaskia, Illinois. Kaskaskia is a very small farming community with a population of 14. Kaskaskia’s claim to fame is that, due to a flood in 1881 that caused a shift in the Mississippi River, the town actually sits on the Missouri side of the River, and is physically separated from the State of Illinois. The area (often called Kaskaskia Island) consists mostly of farm land (lots of corn) and low wetlands that are frequented by shorebirds (it’s a great place to find hundreds of egrets and herons).
After seeing several reports of the Whooping Cranes, I packed my gear very early last weekend and arrived in Kaskaskia before the sun rose. I began cruising the roads throughout Kaskaskia, focusing my attention on the area where the four birds had last been reported. I spent about three hours searching for the elusive Whooping Cranes before abandoning my efforts and crossing the river on the bridge at Chester to see if I could salvage my day with some other birds in southern Illinois.
Friday night (August 26, 2016) I couldn’t sleep at all. I had planned on waking up early to take a trip to Otter Slough near Dexter, Missouri, where I had seen reports of Avocets and Black-necked Stilts. When the clock read 2:00 a.m. and I still hadn’t fallen asleep, I decided I might as well pack my gear and get an early start to Otter Slough. I arrived just as the sun was coming up. Although I never did find the Avocets, I did find a small group of Black-necked Stilts to photograph.
Debating whether I should just go home and take a nap, or try one more spot to photograph, I decided to veer off I-55 and head back to Kaskaskia for one more try at finding the Whooping Cranes. I arrive in the small town around 10:30 a.m. I had lost the good morning light, but there was just enough cloud cover to soften the sun’s rays to avoid overly harsh photographs. I drove straight to the site of the last reported sighting that I had received just 2 days earlier on the Mo-Birds list-serve (an oxbow lake in a cornfield on Cemetery Lane). As I drove down the gravel road, I could see an SUV parked along the side of the road up ahead with a spotting scope on a tripod standing at the edge of the grass. Unless someone was watching the corn grow, I suspected that I had finally found my Whooping Cranes.
Bird watchers are always some of the friendliest people. As I pulled up one of the gentlemen waved me over and handed me his binoculars, pointing out several hundred yards to some white objects at the far end of the shallow oxbow lake surrounded by corn stalks. “Whooping Cranes?” I asked. “Whoppers,” he joked, referring to a report he had read on a list-serve that had misspelled the name. I looked through the binoculars and there they were - - four adult Whooping Cranes leisurely foraging in the shallow waters for food.
I quickly grabbed my camera with a 600mm lens and decided that since the birds were so far out, I would add a 2x teleconverter to the set up to provide maximum magnification. I walked to the edge of the oxbow lake and began shooting, being very careful to walk slowly and remain silent so as not to spook the endangered birds. As I did, the Whooping Cranes began slowly walking towards me. For a good 30 to 40 minutes, the Whooping Cranes kept wading closer and closer as I kept shooting. Eventually, they came so close that I had to remove the 2x teleconverter to keep them from overfilling the frame!
The Whooping Cranes ended up stopping within 40 feet or so of my location. I backed up several times to try to maintain my distance, but they clearly had little fear of humans (which is a problem for their survival). As you can see, all four birds are banded with radio transmitters on both legs (note the antenna). Although I’m sure these four have been reported many times by others over the past couple of days, I went ahead and reported their bands to the U.S. Fish & Wildlife Service.
These are incredible birds. They stood a good 4+ feet tall each and were peaceful and gentle. After they got a good look at me, and I got several hundred good photographs of them, they began to wade back in the direction they came. All-in-all, a pretty good photo day.
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Mineral/Mica Displays, Mining Images, Small and Large Terrariums, interactive touch screen display, tree ring timeline table @ Murphys Point VC Photo taken by Brock Ogilvie
ift.tt/201cW5P Snow fort built by the Tsar, his daughters and soldiers during captivity in Tobolsk, Siberia [448 × 434] 1917-1918 #HistoryPorn #history #retro ift.tt/1sm6Emv via Histolines
Not that I'm competitive or anything, but I just had to post this before Maureen posted hers. You see, we shot this bird at the same time and those are our reflections in his eye. The catchlight is from the sun, not flash. As you can see, he is striking, but he is much smaller than you would think. I would estimate that he is about 12 inches from his feet to the top of his head.
I went to take my kids to see photos in an exhibit by wonderful photographers called Wildlife Beyond Borders 2015 Photography Exhibit in Hayward, California and part of the exhibit today are two beautiful owls that were brought in by Sulphur Creek Nature Center. The kids and I appreciated the wonderful images and most especially seeing the owls up close.
This was taken at the Ingles homestead near Radford. This is where Mary Draper Ingles and her husband lived after she returned from captivity.
From Wikipedia:
Mary Draper Ingles was born in 1732 in Philadelphia, Pennsylvania to George and Elenor (Hardin) Draper, who had immigrated to America from Donegal, Ireland in 1729. In 1748, the Draper family and others moved to the western frontier, establishing Draper's Meadow, a pioneer settlement near modern day Blacksburg, Virginia. Mary married fellow settler William Ingles in 1750, and gave birth to two sons, Thomas in 1751 and George in 1753.
In July, 1755, a band of Shawnee warriors raided Draper's Meadow, (see Draper's Meadow massacre) killing four settlers, one an infant, and taking five hostages, including Mary and her two sons, her sister-in-law Bette Draper, and a male neighbor. The Indians and their captives traveled for a month to a Shawnee village on the banks of the Scioto and Ohio Rivers. Here Mary was separated from her sons, after which she was brought to Big Bone Lick, Kentucky. Some sources suggest that Mary gave birth to a daughter while in captivity (Hale 1886). As a prisoner, Mary sewed shirts and was enslaved to make salt for the Indians. In October, Mary and another captive woman (referred to as the "old Dutch woman" in many sources) escaped from their captors, making their way on foot through the wilderness to return home. Their route followed the Ohio, Kanawha, and New Rivers and they traveled as much as five to six hundred miles, and arrived home after more than 40 days.
After recovering from her journey and reuniting with her husband, Mary went on to have four more children: Mary, Susan, Rhoda (b.1762), and John (b.1766). George died in Indian captivity, but Thomas was ransomed and returned to Virginia in 1768; he underwent several years of rehabilitation and education under Dr. Thomas Walker at Castle Hill, Virginia. William and Mary established Ingles Ferry across the New River in 1762, and she died there in 1815 at the age of 83.
20/100 Possibilities~ 100 Possibilities Project set
en.wikipedia.org/wiki/Martin_Luther_King,_Jr.
Martin Luther King, Jr. (January 15, 1929 – April 4, 1968) was an African American clergyman, activist and prominent leader in the American civil rights movement.
www.americanrhetoric.com/speeches/mlkihaveadream.htm
I am happy to join with you today in what will go down in history as the greatest demonstration for freedom in the history of our nation. Five score years ago, a great American, in whose symbolic shadow we stand today, signed the Emancipation Proclamation. This momentous decree came as a great beacon light of hope to millions of Negro slaves who had been seared in the flames of withering injustice. It came as a joyous daybreak to end the long night of their captivity. But one hundred years later, the Negro still is not free. One hundred years later, the life of the Negro is still sadly crippled by the manacles of segregation and the chains of discrimination. One hundred years later, the Negro lives on a lonely island of poverty in the midst of a vast ocean of material prosperity. One hundred years later, the Negro is still languished in the corners of American society and finds himself an exile in his own land.
And so we've come here today to dramatize a shameful condition. In a sense we've come to our nation's capital to cash a check. When the architects of our republic wrote the magnificent words of the Constitution and the Declaration of Independence, they were signing a promissory note to which every American was to fall heir. This note was a promise that all men, yes, black men as well as white men, would be guaranteed the "unalienable Rights" of "Life, Liberty and the pursuit of Happiness." It is obvious today that America has defaulted on this promissory note, insofar as her citizens of color are concerned. Instead of honoring this sacred obligation, America has given the Negro people a bad check, a check which has come back marked "insufficient funds."
But we refuse to believe that the bank of justice is bankrupt. We refuse to believe that there are insufficient funds in the great vaults of opportunity of this nation. And so, we've come to cash this check, a check that will give us upon demand the riches of freedom and the security of justice. We have also come to this hallowed spot to remind America of the fierce urgency of Now. This is no time to engage in the luxury of cooling off or to take the tranquilizing drug of gradualism.
Now is the time to make real the promises of democracy. Now is the time to rise from the dark and desolate valley of segregation to the sunlit path of racial justice. Now is the time to lift our nation from the quicksands of racial injustice to the solid rock of brotherhood. Now is the time to make justice a reality for all of God's children.
It would be fatal for the nation to overlook the urgency of the moment. This sweltering summer of the Negro's legitimate discontent will not pass until there is an invigorating autumn of freedom and equality. Nineteen sixty-three is not an end, but a beginning. And those who hope that the Negro needed to blow off steam and will now be content will have a rude awakening if the nation returns to business as usual. And there will be neither rest nor tranquility in America until the Negro is granted his citizenship rights. The whirlwinds of revolt will continue to shake the foundations of our nation until the bright day of justice emerges.
But there is something that I must say to my people, who stand on the warm threshold which leads into the palace of justice: In the process of gaining our rightful place, we must not be guilty of wrongful deeds.
Let us not seek to satisfy our thirst for freedom by drinking from the cup of bitterness and hatred.
We must forever conduct our struggle on the high plane of dignity and discipline. We must not allow our creative protest to degenerate into physical violence. Again and again, we must rise to the majestic heights of meeting physical force with soul force. The marvelous new militancy which has engulfed the Negro community must not lead us to a distrust of all white people, for many of our white brothers, as evidenced by their presence here today, have come to realize that their destiny is tied up with our destiny.
And they have come to realize that their freedom is inextricably bound to our freedom. We cannot walk alone. And as we walk, we must make the pledge that we shall always march ahead. We cannot turn back.
There are those who are asking the devotees of civil rights, "When will you be satisfied?" We can never be satisfied as long as the Negro is the victim of the unspeakable horrors of police brutality. We can never be satisfied as long as our bodies, heavy with the fatigue of travel, cannot gain lodging in the motels of the highways and the hotels of the cities. We cannot be satisfied as long as the negro's basic mobility is from a smaller ghetto to a larger one. We can never be satisfied as long as our children are stripped of their self-hood and robbed of their dignity by signs stating: "For Whites Only." We cannot be satisfied as long as a Negro in Mississippi cannot vote and a Negro in New York believes he has nothing for which to vote.
No, no, we are not satisfied, and we will not be satisfied until "justice rolls down like waters, and righteousness like a mighty stream."
I am not unmindful that some of you have come here out of great trials and tribulations. Some of you have come fresh from narrow jail cells. And some of you have come from areas where your quest -- quest for freedom left you battered by the storms of persecution and staggered by the winds of police brutality. You have been the veterans of creative suffering. Continue to work with the faith that unearned suffering is redemptive. Go back to Mississippi, go back to Alabama, go back to South Carolina, go back to Georgia, go back to Louisiana, go back to the slums and ghettos of our northern cities, knowing that somehow this situation can and will be changed.
Let us not wallow in the valley of despair, I say to you today, my friends. And so even though we face the difficulties of today and tomorrow, I still have a dream. It is a dream deeply rooted in the American dream.
I have a dream that one day this nation will rise up and live out the true meaning of its creed: "We hold these truths to be self-evident, that all men are created equal."
I have a dream that one day on the red hills of Georgia, the sons of former slaves and the sons of former slave owners will be able to sit down together at the table of brotherhood. I have a dream that one day even the state of Mississippi, a state sweltering with the heat of injustice, sweltering with the heat of oppression, will be transformed into an oasis of freedom and justice.
I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character.
I have a dream today! I have a dream that one day, down in Alabama, with its vicious racists, with its governor having his lips dripping with the words of "interposition" and "nullification" -- one day right there in Alabama little black boys and black girls will be able to join hands with little white boys and white girls as sisters and brothers. I have a dream today! I have a dream that one day every valley shall be exalted, and every hill and mountain shall be made low, the rough places will be made plain, and the crooked places will be made straight; "and the glory of the Lord shall be revealed and all flesh shall see it together."
This is our hope, and this is the faith that I go back to the South with. With this faith, we will be able to hew out of the mountain of despair a stone of hope.
With this faith, we will be able to transform the jangling discords of our nation into a beautiful symphony of brotherhood.
With this faith, we will be able to work together, to pray together, to struggle together, to go to jail together, to stand up for freedom together, knowing that we will be free one day.
And this will be the day -- this will be the day when all of God's children will be able to sing with new meaning:
My country 'tis of thee, sweet land of liberty, of thee I sing.
Land where my fathers died, land of the Pilgrim's pride,
From every mountainside, let freedom ring!
And if America is to be a great nation, this must become true.
And so let freedom ring from the prodigious hilltops of New Hampshire. Let freedom ring from the mighty mountains of New York. Let freedom ring from the heightening Alleghenies of Pennsylvania. Let freedom ring from the snow-capped Rockies of Colorado. Let freedom ring from the curvaceous slopes of California. But not only that: Let freedom ring from Stone Mountain of Georgia. Let freedom ring from Lookout Mountain of Tennessee. Let freedom ring from every hill and molehill of Mississippi. From every mountainside, let freedom ring.
And when this happens, when we allow freedom ring, when we let it ring from every village and every hamlet, from every state and every city, we will be able to speed up that day when all of God's children, black men and white men, Jews and Gentiles, Protestants and Catholics, will be able to join hands and sing in the words of the old Negro spiritual:
Free at last! Free at last! Thank God Almighty, we are free at last!
Babirusa in captivity at the Naemundung Animal Collection, Sulawesi, Indonesia.This zoo is located between Manado and Tongkoko National Park.
Photographed in captivity using Olympus OM-D E-M10 Mk4 and Laowa 50mm f/2.8 2X Ultra Macro.
View more at Sulawesi Shrimps
Those are the new borns in St-Felicien Zoo. They were born under captivity something really rare for polar bears.
It was a really warm day and they were sleeping under the hot sun(30c).
There is a contest to find name for those cubs: www.zoosauvage.org/article_ete_en.php?id_article=184
This caribou was in a very small enclosure for the benefit of tourists in Alaska. I was informed that it is only in this very small enclosure for the "shows." It was fascinating to see and to get so close (look at the blood on the antlers!) but tough to accept as a necessity.
The captive children told to march like 'honourable Japanese soldiers'!
White Coolies by Betty Jeffrey 1954.
Following the Fall of Singapore and Malaya in 1942, most of the allied troops and civilians left in the region were taken prisoner by the Japanese.
Jeffrey and 64 other nurses of the Australian Army Nursing Service, were evacuated just prior to the Occupation in the ship ‘Vyner Brooke’, which was bombed and sunk by Japanese bombers. 12 nurses were drowned, 21 were captured and summarily executed by the Japanese, and the remaining 32 taken into captivity.
This account written in secret on scraps of paper by Army Nurse Betty Jeffrey, (1908-2000), details the deprivations and horror suffered by the Australian and British nurses ( also British and Dutch civilian prisoners and their children) at the hands of the Japanese in the POW and labour camps.
Published by Angus & Robertson, Sydney. Illustrated by J.Kickhefer. Green cloth boards, 104 pages, 22cm x 14cm.
My mom send me a small branch of basil enclosed in her letter! I put it in a glass and it is still alive! Basil reminds me of my island! In most of the gardens you will find at least one pot with this plant! So wherever you go during spring and summer you will smell this beautiful plant! I really miss those summer afternoons when people water their flowers and this plant explodes its smell with the smallest touch!!!
A giant tortoise at the Charles Darwin Research Station on Santa Cruz
Galapagos Giant Tortoise
The Galápagos tortoise or Galápagos giant tortoise (Geochelone nigra) is the largest living tortoise, native to seven islands of the Galápagos archipelago. The Galápagos tortoise is unique to the Galápagos Islands. Fully grown adults can weigh over 300 kilograms (661 lb) and measure 1.2 meters (4 ft) long. They are long-lived with a life expectancy in the wild estimated to be 100-150 years. Populations fell dramatically because of hunting and the introduction of predators and grazers by humans since the seventeenth century. Now only ten subspecies of the original twelve exist in the wild. However, conservation efforts since the establishment of the Galápagos National Park and the Charles Darwin Foundation have met with success, and hundreds of captive-bred juveniles have been released back onto their home islands. They have become one of the most symbolic animals of the fauna of the Galápagos Islands. The tortoises have very large shells (carapace) made of bone. The bony plates of the shell are integral to the skeleton, fused with the ribs in a rigid protective structure. Naturalist Charles Darwin remarked "These animals grow to an immense size ... several so large that it required six or eight men to lift them from the ground.". This is due to the phenomenon of island gigantism whereby in the absence of natural predation, the largest tortoises had a survival advantage and no disadvantage in fleeing or fending off predators. When threatened, it can withdraw its head, neck and all forelimbs into its shell for protection, presenting a protected shield to a would-be predator. The legs have hard scales that also provide armour when withdrawn. Tortoises keep a characteristic scute pattern on their shell throughout life. These have annual growth bands but are not useful for aging as the outer layers are worn off. There is little variation in the dull-brown colour of the shell or scales. Physical features (including shape of the shell) relate to the habitat of each of the subspecies. These differences were noted by Captain Porter even before Charles Darwin. Larger islands with more wet highlands such as Santa Cruz and the Alcedo Volcano on Isabela have lush vegetation near the ground. Tortoises here tend to have 'dome-back' shells. These animals have restricted upward head movement due to shorter necks, and also have shorter limbs. These are the heaviest and largest of the subspecies.Smaller, drier islands such as Española and Pinta are inhabited by tortoises with 'saddleback' shells comprising a flatter carapace which is elevated above the neck and flared above the hind feet. Along with longer neck and limbs, this allows them to browse taller vegetation. On these drier islands the Galápagos Opuntia cactus (a major source of their fluids) has evolved a taller, tree-like form. This is evidence of an evolutionary arms race between progressively taller tortoises and correspondingly taller cacti. Saddlebacks are smaller in size than domebacks. They tend to have a yellowish color on lower mandible and throat. At one extreme, the Sierra Negra volcano population that inhabits southern Isabela Island has a very flattened "tabletop" shell. However, there is no saddleback/domeback dualism; tortoises can also be of 'intermediate' type with characteristics of both. The tortoises are slow-moving reptiles with an average long-distance walking speed of 0.3 km/h (0.18 mph). Although feeding giant tortoises browse with no apparent direction, when moving to water-holes or nesting grounds, they can move at surprising speeds for their size. Marked individuals have been reported to have traveled 13 km in two days. Being cold-blooded, the tortoises bask for two hours after dawn, absorbing the energy through their shells, then becoming active for 8–9 hours a day. They may sleep for about sixteen hours in a mud wallow partially or submerged in rain-formed pools (sometimes dew ponds formed by garua-moisture dripping off trees). This may be both a thermoregulatory response and a protection from parasites such as mosquitoes and ticks. Some rest in a 'pallet'- a snug depression in soft ground or dense brush- which probably helps to conserve heat and may aid digestion. On the Alcedo Volcano, repeated use of the same sites by the large resident population has resulted in the formation of small sandy pits. Darwin observed that: "The inhabitants believe that these animals are absolutely deaf; certainly they do not overhear a person walking near behind them. I was always amused, when overtaking one of these great monsters as it was quietly pacing along, to see how suddenly, the instant I passed, it would draw in its head and legs, and uttering a deep hiss fall to the ground with a heavy sound, as if struck dead." The tortoises can vocalise in aggressive encounters, whilst righting themselves if turned upside down and, in males, during mating. The latter is described as "rhythmic groans". The tortoises are herbivorous animals with a diet comprising cactus, grasses, leaves, vines, and fruit. Fresh young grass is a favorite food of the tortoises, and others are the 'poison apple' (Hippomane mancinella) (toxic to humans), the endemic guava (Psidium galapageium), the water fern (Azolla microphylla), and the bromeliad (Tillandsia insularis). Tortoises eat a large quantity of food when it is available at the expense of incomplete digestion. Its favorite food is grasses. The tortoise normally eat an average of 70 to 80 pounds a day. Tortoises have a classic example of a mutualistic symbiotic relationship with some species of Galápagos finch. The finch hops in front of the tortoise to show that it is ready and the tortoise then raises itself up high on its legs and stretches out its neck so that the bird can pick off ticks that are hidden in the folds of the skin (especially on the rear legs, cloacal opening, neck, and skin between plastron and carapace), thus freeing the tortoise from harmful parasites and providing the finch with an easy meal. Other birds, including Galápagos Hawk and flycatchers, use tortoises as observation posts from which to sight their prey. Mating occurs at any time of the year, although it does have seasonal peaks between January and August. When two mature males meet in the mating season they will face each other, rise up on their legs and stretch up their necks with their mouths open to assess dominance. Occasionally, head-biting occurs, but usually the shorter loser tortoise will back off, leaving the other to mate with the female. In groups of tortoises from mixed island populations, saddleback males have an advantage over domebacks. Frustrated non-dominant males have been observed attempting to mate with other males and boulders. The male sniffs the air when seeking a female, bellows loudly, and bobs his head. The male then rams the female with the front of his shell and bites her exposed legs until she withdraws them, immobilizing her. Copulation can last several hours with roaring vocalisations from the males. Their concave shell base allows males to mount the females from behind. It brings its tail which houses the penis into the female's cloaca. After mating (June-December), the females journey up to several kilometres to reach nesting areas of dry, sandy ground (often near the coast). Nest digging can last from hours to days and is elaborate and exhausting. It is carried out blindly using only the hind legs to dig a 30 cm deep hole, into which she lays up to sixteen hard-shelled eggs the size of tennis balls. The female makes a muddy plug for the nest hole out of soil mixed with urine and leaves the eggs to incubate. In rocky areas, the eggs are deposited randomly into cracks. The young emerge from the nest after 120 to 140 days gestation later (December-April) and may weigh only 80 grams (2.8 oz) and measure 6 centimetres (2.4 in). Temperature plays a role in the sex of the hatchling: if the nest temperature is lower, more males will hatch; if it is high, more females will hatch. When the young tortoises emerge from their shells, they must dig their way to the surface, which can take up to a month. All have domed carapaces, and subspecies are indistinguishable. Galápagos Hawk used to be the only native predator of the tortoise hatchlings, as Darwin remarked: "The young tortoises, as soon as they are hatched, fall prey in great numbers to buzzards". Sex can be determined only when the tortoise is 15 years old, and sexual maturity is reached at 20 to 25 years old. The tortoises grow slowly for about 40 years until they reach their full size. Reproductive prime is considered to be from the ages of 60–90. The shape of the carapace of some subspecies of the tortoises is said to have reminded the early Spanish explorers of a kind of saddle they called a "galápago," and for these saddle-shaped tortoises they named the archipelago. Up to 250,000 tortoises inhabited the islands when they were discovered. Today only about 15,000 are left.
The inhabitants...state that they can distinguish the tortoise from different islands; and that they differ not only in size, but in other characters. Captain Porter has described those from Charles and from the nearest island to it, namely Hood Island, as having their shells in front thick and turned up like a Spanish saddle, whilst the tortoises from James Island are rounder, blacker, and have a better taste when cooked.---Charles Darwin 1845
There were probably twelve subspecies of Geochelone nigra in the Galápagos Islands, although some recognise up to 15 subspecies. Now only 11 subspecies remain, five on Isabela Island, and the other six on Santiago, Santa Cruz, San Cristóbal, Pinzón, Española and Pinta. Of these, the Pinta Island subspecies is extinct in the wild and is represented by a single individual (Lonesome George). In the past, zoos took animals without knowing their island of origin. Production of fertile offspring from various pairings of tortoises largely confirmed that they are subspecies and not different species. All the subspecies of giant tortoise evolved in Galápagos from a common ancestor that arrived from the mainland, floating on the ocean currents (the tortoises can drift for long periods of time as they are buoyant and can stretch head upwards to breathe). Only a single pregnant female or breeding pair needed to arrive in this way, and then survive, for Galápagos to be colonised. In the seventeenth century, pirates started to use the Galápagos islands as a base for resupply, restocking on food, water and repairing vessels before attacking Spanish colonies on the South American mainland. The tortoises were collected and stored live on board ships where they could survive for at least a year without food or water, providing valuable fresh meat, whilst their diluted urine and water stored in their neck bags could also be used as drinking water. Of the meat, Darwin wrote: "the breast-plate roasted (as the Gauchos do 'carne con cuero'), with the flesh on it, is very good; and the young tortoises make excellent soup; but otherwise the meat to my taste is indifferent." In the nineteenth century, whaling ships and fur-sealers collected tortoises for food and many more were killed for high grade 'turtle oil' from the late 1800s onward. Darwin described this process thus: "beautifully clear oil is prepared from the fat. When a tortoise is caught, the man makes a slit in the skin near its tail, so as to see inside its body, whether the fat under the dorsal plate is thick. If it is not, the animal is liberated and it is said to recover soon from this strange operation." A total of over 15,000 tortoises is recorded in the logs of 105 whaling ships between 1811 and 1844. As hunters found it easiest to collect the tortoises living round the coastal zones, the least decimated populations tended to be those in the highlands. Population decline accelerated with the early settlement of the islands, when they were hunted for meat, their habitat was cleared for agriculture and alien mammal species were introduced. Feral pigs, dogs, cats and black rats are effective predators of eggs and young tortoises, whilst goats, donkeys and cattle compete for grazing. In the twentieth century, increasing human settlement and urbanisation and collection of tortoises for zoo and museum specimens depleted numbers even more. The Galápagos giant tortoise is now strictly protected. Young tortoises are raised in a programme by the Charles Darwin Research Station in order to bolster the numbers of the extant subspecies. Eggs are collected from places on the islands where they are threatened and when the tortoises hatch they are kept in captivity until they have reached a size that ensures a good chance of survival and are returned to their original ranges. The Galápagos National Park Service systematically culls feral predators and competitors where necessary such as the complete eradication of goats from Pinta. The conservation project begun in the 1970s successfully brought 10 of the 11 endangered subspecies up to guarded population levels. The most significant recovery was that of the Española Tortoise, whose breeding stock comprised 2 males and 11 females brought to the Darwin Station. Fortuitously, a third male was discovered at the San Diego Zoo and joined the others in a captive breeding program. These 13 tortoises gave rise to over 1000 tortoises now released into their home island. In all, 2500 individuals of all breeds have been reintroduced to the islands. However, persecution still continues on a much smaller scale; more than 120 tortoises have been killed by poachers since 1990 and they have been taken hostage as political leverage by local fishermen.
Santa Cruz
With the largest human population in the Galapagos archipelago, Isla Santa Cruz is the most important of the Galapagos Islands. Meaning Holy Cross in Spanish, this island is also known as Indefatigable, after the HMS Indefatigable landed here long ago. The second largest island terms of land area at 986 sq km, Isla Santa Cruz is home to the key town of Puerto Ayora, the Charles Darwin Research Station and the headquarters of the Galapagos National Park Service. With its own airport on Isla Baltra a few miles away, Isla Santa Cruz is where most visitors who come to the Galapagos Islands usually stay. With a number of bars, hotels, restaurants and shops in Puerto Ayora, most tours of the Archipelago also usually begin from here.
Galapagos Islands
The Galápagos Islands (official name: Archipiélago de Colón; other Spanish names: Islas de Colón or Islas Galápagos) are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, some 900 km west of Ecuador. It is a UNESCO World Heritage site: wildlife is its most notable feature. Because of the only very recent arrival of man the majority of the wildlife has no fear of humans and will allow visitors to walk right up them, often having to step over Iguanas or Sea Lions.The Galápagos islands and its surrounding waters are part of a province, a national park, and a biological marine reserve. The principal language on the islands is Spanish. The islands have a population of around 40,000, which is a 40-fold expansion in 50 years. The islands are geologically young and famed for their vast number of endemic species, which were studied by Charles Darwin during the voyage of the Beagle. His observations and collections contributed to the inception of Darwin's theory of evolution by natural selection.
28 November, 2015 - Update on the captives in Taiji, Japan
The global captivity industry is the main driver of the brutal and barbaric drive and slaughter of thousands of dolphins and whales every year.
The only captured pilot whale from the drive on November 19 2015 (Japan time), is seen being forcefed by whale museum trainers in the harbor pens of Taiji. He/She showed little movement and refused to eat for seven days. The pilot whale is clearly outnumbered, and a sling is the weapon of choice for these trainers. It`s used to rip innocent families apart, then used to trap the dolphins against the side of the pens to forcefeed and perform tests.
Dolphins and whales in captivity show signs of depression, and torture begins for captives inside the cove and continues every day after. Say NO to captivity! Don`t buy a ticket!
Sites for more information :
Sea Shepherd Cove Guardians Page (official)
www.facebook.com/SeaShepherdCoveGuardiansOfficialPage
Cove Guardians
www.seashepherd.org/cove-guardians
Photo: Sea Shepherd
Oct 24, 2023, 18th Day of the Gaza/Hamas War
Post 21 by Tsiel Ohayon.
"There was a lot of talk and speculation last night about the release of 50 hostages, mainly the ones holding dual citizenship. Apparently that deal has collapsed due to Hamas’ insistence on receiving fuel in exchange for the 50 hostages. However, 2 Israeli ladies, Yocheved Lifshitz, age 85 and Nurit Kuper, age 80, were released on “humanitarian” ground, unfortunately their husbands are still captive in Gaza. Since when is Hamas thoughtful of Humanitarian issues? What a joke!
Both ladies were abducted from their Nahal Oz homes on Oct 7th. While they both looked tired from their ordeal, hospital officials mentioned that they are doing fine, especially after what they have just experienced. Yocheved talked to the press this morning and said that she had walked a few kilometers underground in Gaza, in a large tunnel complex which in the end led to a bigger room where 25 captives were held. They were separated into groups of 5 and each captive was assigned a guard. Many things said during the press conference were said under duress as her husband is still in captivity. I am assuming that Hamas gave her instructions on what needed to be said to keep her husband alive. I suggest that we don’t fall in any trap thinking Hamas was nice to these people and treated them humanely during their captivity. Let’s not forget, she and the 221 others should never have been in Gaza in the first place. One more word about Yocheved and her husband. For the last 10-15 years they have been driving every week to the Erez crossing, one of the main border crossings between Israel and Gaza. They have been taking in their own car, sick Palestinians who needed treatment in Israeli hospitals. They would go around the country to take these people where they had to go. They would wait for the daily treatment to end and take them back to the crossing in the evening. Hamas didn’t care, Hamas killed, plundered, and captured even those who tried to help their own people. Hamas doesn’t care about their people; this is another example.
The Israeli army dropped leaflets on Gaza saying that any Gazan who would bring information about the hostages would be rewarded. Hamas works in compartments, groups are separated and don’t communicate, not sure civilians will be able to help, unless it’s one of the captors who wants to turn his vest.
Dr. Amit Frankel is a medical doctor at Soroka Hospital in Beer Sheva. Nothing prepared the hospital to receive 100s of wounded on Oct 7th. In the first 3h of the morning he performed and helped perform 318 lifesaving procedures. By the end of the first day, he had treated 600 people. Hero. We never talk enough about those working in the hospitals day and night to save lives. As of today, there are still 278 people treated in Israeli hospitals, 40 of them in serious condition, 164 in medium condition and 74 lightly wounded. On October 9th, 2616 people had been hospitalized, 25 in critical condition, 357 in serious condition, 524 in medium condition and the rest lightly wounded.
The family of Amer Abu Sabila, 25 years old from Abu Talul from the Bedouin community, received official notification yesterday (Monday) about the identification of Amer’s body. Amer, who was married and the father of two children, aged four and two, was murdered in the Hamas terrorist attack near the police station in Sderot. He was shot dead while trying to save Odeya Suissa and her daughters, aged 6 and 3, after the family's father, Dolev, was murdered while they were on their way to escape the city. The Suissa family encountered the Hamas terrorists in Sderot near the commercial complex, and to save their lives, the father and mother split up, each of them taking one of the girls with them. They tried to hide, but in vain: the terrorists shot Dolev and wounded him, and he later died of his wounds. The girl who was with the father was not hurt, and instead ran away to her mother and sister. Amer, saw the scene and understood that Odeya was not in a mental state to drive. They saw a policeman who told them to come to the Sderot police station by following his patrol car. As they arrived, gunmen were already shooting at the police station. The policeman, Amer and Odeya were shot and killed. The little girls in the back were unhurt. Again, we see that Arabs helped Jews and vice versa in the wake of these senseless atrocities. The Bedouins of Israel have been serving in the Israeli Army for years, mainly as trackers. Many have fallen for the protection of the State of Israel. Amer is another example. As a population, we are all in this together. May he and the Suissa parents rest in peace and may the little girls have strength and courage to overcome this difficult period.
Last night, the Shabak (Israel internal security services) released some footage of captured Hamas prisoners while being investigated. They all deserve to be executed. However, the information provided to the Shabak is probably priceless. Two main things come out of these interrogations. A captured Israeli was worth 10,000 dollars and an apartment. I don’t think many Hamas terrorists will be getting an apartment soon unless they can live under slabs of ruins. The other thing that came out was the order to kill and kill and kill, as many as possible. Kill the “useless ones” and try to bring back some “useful ones”. Do they really believe that we are going to free bloodthirsty Hamas terrorists that are in our jails so that we can get more of these atrocities? Most if not all released from the Gilad Shalit deal are either part of the Hamas Leadership today or took part in the Oct 7th massacres. Enough. The exchange rate is simple. Hamas provided it last time. For every Israeli that is hurt in captivity, 1027 Palestinian prisoners should be executed. Sounds harsh … sounds undemocratic? Sounds fascistic?
This is war, and we need to speak the only language these people understand. The hostages should be ALL released at no cost and the sooner the better, even for the Palestinians.
Israeli security sources also released a recording of a Hamas Terrorist (apparently called Mahmud) who had infiltrated kibbutz Mefalsim, the morning of Oct 7th. He took the phone of one of his victims and called his parents to tell them how proud they should be of him as he had killed 10 Jews. He then told them to look at their WhatsApp as he sent pictures of the ones he had killed with his bare hands (in his language). His father congratulated him, his mother was choked with joy and crying, and his father told him to come home. He said: “Home? It’s either victory or martyrdom for this beautiful religion that you brought me in” … Monsters did we say? Probably even worse.
French President Emmanuel Macron has made a visit today to Israel. After meeting with the families of 30+ French nationals killed or captured by Hamas, he held political discussions with President Herzog, Prime Minister Netanyahu and one of the Opposition leaders Benny Gantz. President Macron was firm about condemning Hamas and understands the suffering of the Palestinian people in Gaza. He will meet later tonight with PA President Mahmoud Abbas. Macron also said that his country doesn’t believe Hezbollah want war. Lebanon can’t afford a war. The price will be very high for both sides, but if I were Nasrallah, I wouldn’t test our patience too much. In any case, what does Macron know.
Before I give an update on what’s happening on various fronts, I heard three interesting analyses today.
The first analysis is about the Iron Dome. The Iron Dome is a defensive weapon that blows rockets out of the sky. In real-time it calculates the rocket’s trajectory and if found to be dangerous (i.e. falling into a populated area), an Iron Dome missile is automatically fired to intercept the rocket. The system has been effective now for over 12 years. This has given a sense of security to Israelis that even if a couple of rockets get through the system, nothing really terrible is happening. If we didn’t have the Iron Dome, analysts say we would have eliminated Hamas much sooner as life without the Iron Dome would have been unbearable. Probably true.
The second analysis is about the army’s ineffectiveness on the first day of the war. According to the blogger I watched, Hamas had already placed sleeper cells in the country that were dispersed in Bedouin communities. Before the hordes of terrorists crossed the border, these sleeper cells attacked all army bases around the strip killing all of the scouts and observers manning the border. Once those “eyes” were out of commission, the “Hamas army” could come in and commit their atrocities. This is based on timings that some bases were reportedly attacked at 6:15 am, when Hamas hordes crossed into Israel at approximately 6:45 am. This is something to look into. I hope that if true, we have learned our lesson, stay vigilant and make sure the same is not going to happen in the North with Hezbollah.
The third analysis is from Eitan Ben Eliyahu, the former Israel Air Commander. He said, and rightly so, that errors in understanding intelligence information will always happen. You might have all of the data, but your conclusions are either wrong or you are not reading the data correctly. It doesn’t matter, it will always happen. He rightly says that with or without intelligence, your forces should always be ready for combat, otherwise there is no reason to have them there. There is no room for complacency in the Middle East, you always need to have your finger on the trigger.
On the Southern front, a senior military official, speaking on the condition of anonymity, revealed to the Saudi news site "Eilaf" the reasons for the delay in ground operations in the Gaza Strip - according to him, the allied countries, primarily the United States - fully support the ground entry. However, the allies want Israel to make sure it takes the necessary precautions regarding innocent Gazan civilians while leaving a humanitarian aid corridor open. According to the official, one of the reasons for delaying the ground entry is the Israeli desire to eliminate as many operatives and terrorists of the Hamas military wing as possible, as well as to attack headquarters, observation points and rocket launchers from the air. So that there will be no obstacles for the forces that will enter the strip. The second reason, according to the official, is to give the population of Gaza and the citizens more time to move from the north to the south of the Strip and evacuate the populated areas that the terrorist organization Hamas uses for its operations and to avoid Hamas using Gazans as human shields. Another reason is that Israel is using the time until the entry to train its forces better. According to him, all the training complexes in Israel witness an intensive presence of training soldiers, at the same time as the flow of weapons and equipment that will be used by Israel in the ground entrance. In addition, at the same time as the Air Force strikes, engineering forces and other forces are working on arrangements for the establishment of a buffer zone in the border area before the ground entry in order to ensure the survival of that area even after the end of the war and the achievement of its goals, which are to put an end to the military capability of Hamas and collapse its rule.
Regarding what is happening, more of the same basically. Over 400 aerial sorties, more Gaza buildings and neighborhoods destroyed, while Hamas and its friends launch more rockets into Israel. The rocket fire was mostly calm today, but a large salvo was fired at 5pm towards Tel Aviv, the Sharon and Shfela regions. There doesn’t seem to be any interruption in the war. However, there are some signs that the Gaza population is now starting to tire, and it questions Hamas’ strategy as the war has only brought destruction, death, and worldwide condemnation. The Palestinian cause has lost a lot of its credibility (at least at government levels) through Hamas’ actions. The Hamas is ISIS campaign has proven to be very effective.
In the evening, Hamas Frogmen tried to storm the Zikim kibbutz and beach just North of Gaza. The Israeli Navy and an elite commando unit killed the infiltrators, as of writing 7 frogmen are known dead, and maybe several more are unconfirmed. The number of Israeli casualties is currently undisclosed. The Naval base from which they departed was blasted to pieces as well. it seems there was a tunnel departing from the land that brought the men directly into the sea to evade the “eyes” of the Israeli army. Need to beware that Hezbollah could have the same in the North out of Ras Naqoura.
The Northern front was relatively calm today until dusk, a few skirmishes here and there but nothing different from what we have seen in the last week or so. At dusk, mortars and rockets were fired at Israeli outposts. Israel returned fire and hit a school in Ayta as Shaab, approx. 1km from the Israeli border. The rockets and mortars had been fired from the school compound. It is estimated that 50 Hezbollah fighters have been killed up to now. South Lebanese have mainly left the South and moved North hoping for better days.
From the Syrian Golan, with its large contingent of Iranian proxy soldiers waiting to storm the border, five rockets were fired towards the Israeli Golan heights, 2 fell on the Israeli side in open fields, 3 on the Syrian. This is the beginning of hostilities on that front. Israel returned fire towards the source. – usual army language. We need to be careful this is not a diversion attempt for something more important elsewhere.
In Syria and Iraq, Iranian proxies have attacked about 15 times US bases; Al Harir, Ein Al Asad, and Irbil Airport in Iraq; Al Tanaf, Al Rochban, Al Omar oil field, Koniko, Al Shadadi and Al Malkia in Syria. American officials believe that there will be a rapid increase in the number of attacks against US interests in the region. Two unconfirmed rumors state that one US base in Saudi Arabia has also been attacked as well as US shipping interests near Yemen. I need to follow up on those rumors as they could have significant developments in the future. The US are beefing up their forces in the region with an additional F-16 squadron which has been dispatched to the region. More men and material are being sent to the main bases in Syria and Iraq. The US’ reaction to Iranian backed proxy attacks is awaited, not just from us Israelis, but from all the enemies, especially Iran. The nature of America’s response will determine the course of the war.
Internally, Israel is cracking down on anybody showing any kind of sympathy for Hamas. Those sympathizers are swiftly arrested and interrogated. I would, also, like to put in a good word about the Arab population of Israel (20% of the pop) who for the moment have understood the gravity of the situation and who have mostly distanced themselves from Hamas and its actions. Several Israeli-Arab leaders, such as Mansur Abbas and Ayman Odeh, have been very clear about what has happened and have called upon the Arab population not to take advantage of the situation. This is a very responsible act on their part. In any case, the police and army have little patience and it would be best to stay put as much as possible. We, also, note that the violence in the Arab communities (many killings and settling of accounts) has drastically diminished since the beginning of the war. This is a good development and lets hope it continues.
Let’s keep our heads high and look forward to a victorious future. The road will be long and arduous, but the goal is understood by all.
Am Yisrael Hai!"