Scott Hanko
Gila Monster
The Gila monster ( /ˈhiːlə/ hee-lə), Heloderma suspectum, is a species of venomous lizard native to the southwestern United States and northwestern Mexican state of Sonora. A heavy, slow-moving lizard, up to 60 centimetres (2.0 ft) long, the Gila monster is the only venomous lizard native to the United States and one of only two known species of venomous lizards in North America, the other being its close relative, the Mexican beaded lizard (H. horridum). Though the Gila monster is venomous, its sluggish nature means that it represents little threat to humans. However, it has earned a fearsome reputation and is sometimes killed despite being protected by state law in Arizona and Nevada.
The Gila monster is found in the Southwestern United States and Mexico, a range entailing Sonora, Arizona, parts of California, Nevada, Utah, and New Mexico (but not Baja California). They inhabit scrubland, succulent desert, and oak woodland, seeking shelter in burrows, thickets, and under rocks in locations with ready access to moisture. In fact, Gila monsters seem to like water and can be observed immersing themselves in puddles of water after a summer rain. They avoid living in open areas such as flats and farmland.
The Gila monster feeds primarily on bird and reptile eggs, and occasionally upon small birds, mammals, frogs, lizards, insects, and carrion. The Gila monster eats infrequently (only five to ten times a year in the wild), but when it does feed, it may eat up to one-third of its body mass. It uses its extremely acute sense of smell to locate prey, especially eggs. Its sense of smell is so keen that it can locate and dig up chicken eggs buried 15 centimetres (5.9 in) deep and accurately follow a trail made by rolling an egg.
Prey may be crushed to death if large or eaten alive if small, swallowed head-first and helped down by muscular contractions and neck flexing. Unusually, after food has been swallowed, the Gila monster immediately resumes tongue flicking and search behavior, probably as a result of a history of finding clumped prey such as eggs and babies in nests. Gila monsters are able to climb trees and cacti in search of eggs.
Venom is produced in modified salivary glands in the Gila monster's lower jaw, unlike snakes, whose venom is produced in the upper jaw. The Gila monster lacks the musculature to forcibly inject the venom; instead, the venom is propelled from the gland to the tooth by chewing. Capillary action brings the venom out of the tooth and into the victim. The teeth are loosely anchored, which allows them to be broken off and replaced throughout life. Gila monsters have been observed to flip over while biting the victim, presumably to aid the flow of the venom into the wound. Because the Gila monster's prey consists mainly of eggs, small animals, and otherwise "helpless" prey, it is thought that the Gila monster's venom evolved for defensive rather than for hunting use. A defensive use would explain the Gila monster's bright warning coloration.
Although the venom is a neurotoxin as toxic as that of a Coral Snake, H. suspectum produces only small amounts.[9] The Gila monster's bite is normally not fatal to adult humans. There are no confirmed reports of fatalities after 1939, and those prior to that year are suspect due to the primitive dangerous "treatments." The Gila monster can bite quickly (especially by swinging its head sideways) and hold on tenaciously and painfully. If bitten, the victim may need to fully submerge the attacking lizard in water to break free from its bite. Symptoms of the bite include excruciating pain, edema, and weakness associated with a rapid drop in blood pressure. More than a dozen peptides and proteins have been isolated from the Gila monster's venom, including hyaluronidase, serotonin, phospholipase A2, and several kallikrein-like glycoproteins responsible for the pain and edema caused by a bite. Four potentially lethal toxins have been isolated from the Gila monster's venom, including horridum venom, which causes hemorrhage in internal organs and exophthalmos (bulging of the eyes), and helothermine, which causes lethargy, partial paralysis of the limbs, and hypothermia in rats. However, the constituents most focused on are the bioactive peptides, including helodermin, helospectin, exendin-3, and exendin-4. Most are similar in form to vasoactive intestinal peptide (VIP), which relaxes smooth muscle and regulates water and electrolyte secretion between the small and large intestines. These bioactive peptides are able to bind to VIP receptors in many different human tissues. One of these, helodermin, has been shown to inhibit the growth of lung cancer.
The Gila monster emerges from hibernation in the months of January or February and mates in May and June. The male initiates courtship by flicking his tongue to search for the female's scent. If the female rejects his advances, she will bite him and crawl away. When successful, copulation has been observed to last from 15 minutes to as long as 2.5 hours. The female will lay eggs in July or August, burying them in sand 12.7 centimetres (5.0 in) below the surface. The clutch consists of two to twelve eggs, with five being the average clutch. The process of incubation lasts nine months, as the hatchlings emerge during the months of April through June the following year. The hatchlings are about 16 centimetres (6.3 in) long and are able to bite and inject venom upon hatching. The juveniles typically have larger bands of pink scales than adults, although the banded Gila monster (H. s. cinctum) has a tendency to retain the band pattern. H. suspectum sexually matures at 3–5 years. After egg-laying, adult Gila monsters gradually spend less time on the surface to avoid the hottest part of the summer (although they may be active in the evening), eventually starting their hibernation around November.
Little is known about the social behavior of H. suspectum, but they have been observed engaging in male-male combat, in which the dominant male lies on top of the subordinate one and pins it with its front and hind limbs. Both lizards arch their bodies, pushing against each other and twisting around in an effort to gain the dominant position. A wrestling match ends when the pressure exerted forces them to separate, although bouts may be repeated over a continuous amount of time. These bouts are typically observed just before the mating season. It is thought that those with greater strength and endurance win more often and enjoy greater reproductive success. Although the Gila monster has a low metabolism and one of the lowest lizard sprint speeds, it has one of the highest aerobic scope values (the increase in oxygen consumption from rest to maximum metabolic exertion) among lizards, allowing them to engage in intense aerobic activity for a sustained period of time. It has been observed that males have a higher aerobic scope than females, presumably because of sexual selection for a trait advantageous in prolonged combat. The Gila monster may live up to 20 years in the wild, or 30 in captivity.
Reptile House
Bronx Zoo New York
Gila Monster
The Gila monster ( /ˈhiːlə/ hee-lə), Heloderma suspectum, is a species of venomous lizard native to the southwestern United States and northwestern Mexican state of Sonora. A heavy, slow-moving lizard, up to 60 centimetres (2.0 ft) long, the Gila monster is the only venomous lizard native to the United States and one of only two known species of venomous lizards in North America, the other being its close relative, the Mexican beaded lizard (H. horridum). Though the Gila monster is venomous, its sluggish nature means that it represents little threat to humans. However, it has earned a fearsome reputation and is sometimes killed despite being protected by state law in Arizona and Nevada.
The Gila monster is found in the Southwestern United States and Mexico, a range entailing Sonora, Arizona, parts of California, Nevada, Utah, and New Mexico (but not Baja California). They inhabit scrubland, succulent desert, and oak woodland, seeking shelter in burrows, thickets, and under rocks in locations with ready access to moisture. In fact, Gila monsters seem to like water and can be observed immersing themselves in puddles of water after a summer rain. They avoid living in open areas such as flats and farmland.
The Gila monster feeds primarily on bird and reptile eggs, and occasionally upon small birds, mammals, frogs, lizards, insects, and carrion. The Gila monster eats infrequently (only five to ten times a year in the wild), but when it does feed, it may eat up to one-third of its body mass. It uses its extremely acute sense of smell to locate prey, especially eggs. Its sense of smell is so keen that it can locate and dig up chicken eggs buried 15 centimetres (5.9 in) deep and accurately follow a trail made by rolling an egg.
Prey may be crushed to death if large or eaten alive if small, swallowed head-first and helped down by muscular contractions and neck flexing. Unusually, after food has been swallowed, the Gila monster immediately resumes tongue flicking and search behavior, probably as a result of a history of finding clumped prey such as eggs and babies in nests. Gila monsters are able to climb trees and cacti in search of eggs.
Venom is produced in modified salivary glands in the Gila monster's lower jaw, unlike snakes, whose venom is produced in the upper jaw. The Gila monster lacks the musculature to forcibly inject the venom; instead, the venom is propelled from the gland to the tooth by chewing. Capillary action brings the venom out of the tooth and into the victim. The teeth are loosely anchored, which allows them to be broken off and replaced throughout life. Gila monsters have been observed to flip over while biting the victim, presumably to aid the flow of the venom into the wound. Because the Gila monster's prey consists mainly of eggs, small animals, and otherwise "helpless" prey, it is thought that the Gila monster's venom evolved for defensive rather than for hunting use. A defensive use would explain the Gila monster's bright warning coloration.
Although the venom is a neurotoxin as toxic as that of a Coral Snake, H. suspectum produces only small amounts.[9] The Gila monster's bite is normally not fatal to adult humans. There are no confirmed reports of fatalities after 1939, and those prior to that year are suspect due to the primitive dangerous "treatments." The Gila monster can bite quickly (especially by swinging its head sideways) and hold on tenaciously and painfully. If bitten, the victim may need to fully submerge the attacking lizard in water to break free from its bite. Symptoms of the bite include excruciating pain, edema, and weakness associated with a rapid drop in blood pressure. More than a dozen peptides and proteins have been isolated from the Gila monster's venom, including hyaluronidase, serotonin, phospholipase A2, and several kallikrein-like glycoproteins responsible for the pain and edema caused by a bite. Four potentially lethal toxins have been isolated from the Gila monster's venom, including horridum venom, which causes hemorrhage in internal organs and exophthalmos (bulging of the eyes), and helothermine, which causes lethargy, partial paralysis of the limbs, and hypothermia in rats. However, the constituents most focused on are the bioactive peptides, including helodermin, helospectin, exendin-3, and exendin-4. Most are similar in form to vasoactive intestinal peptide (VIP), which relaxes smooth muscle and regulates water and electrolyte secretion between the small and large intestines. These bioactive peptides are able to bind to VIP receptors in many different human tissues. One of these, helodermin, has been shown to inhibit the growth of lung cancer.
The Gila monster emerges from hibernation in the months of January or February and mates in May and June. The male initiates courtship by flicking his tongue to search for the female's scent. If the female rejects his advances, she will bite him and crawl away. When successful, copulation has been observed to last from 15 minutes to as long as 2.5 hours. The female will lay eggs in July or August, burying them in sand 12.7 centimetres (5.0 in) below the surface. The clutch consists of two to twelve eggs, with five being the average clutch. The process of incubation lasts nine months, as the hatchlings emerge during the months of April through June the following year. The hatchlings are about 16 centimetres (6.3 in) long and are able to bite and inject venom upon hatching. The juveniles typically have larger bands of pink scales than adults, although the banded Gila monster (H. s. cinctum) has a tendency to retain the band pattern. H. suspectum sexually matures at 3–5 years. After egg-laying, adult Gila monsters gradually spend less time on the surface to avoid the hottest part of the summer (although they may be active in the evening), eventually starting their hibernation around November.
Little is known about the social behavior of H. suspectum, but they have been observed engaging in male-male combat, in which the dominant male lies on top of the subordinate one and pins it with its front and hind limbs. Both lizards arch their bodies, pushing against each other and twisting around in an effort to gain the dominant position. A wrestling match ends when the pressure exerted forces them to separate, although bouts may be repeated over a continuous amount of time. These bouts are typically observed just before the mating season. It is thought that those with greater strength and endurance win more often and enjoy greater reproductive success. Although the Gila monster has a low metabolism and one of the lowest lizard sprint speeds, it has one of the highest aerobic scope values (the increase in oxygen consumption from rest to maximum metabolic exertion) among lizards, allowing them to engage in intense aerobic activity for a sustained period of time. It has been observed that males have a higher aerobic scope than females, presumably because of sexual selection for a trait advantageous in prolonged combat. The Gila monster may live up to 20 years in the wild, or 30 in captivity.
Reptile House
Bronx Zoo New York