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Lifespan, longevity, and ageing

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Maximum longevity: 28.9 years (captivity)
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The Gila monster lacks the ability to jump, contrary to popular myth (Ernst, 1992)

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Stewart, M. 2003. "Heloderma suspectum" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Heloderma_suspectum.html
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Conservation Status

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The lizard is often killed because it is poisonous. The Gila monster is legally protected in all states in which they are found. (Ernst, 1992) (Bogert, 1956)

US Federal List: no special status

IUCN Red List of Threatened Species: near threatened

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Stewart, M. 2003. "Heloderma suspectum" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Heloderma_suspectum.html
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Benefits

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The Gila monster has little economic importance to humans. There is a small market for the hemipenis, which is used as an aphrodisiac. A small "pet" market for the species has also arisen. It is illegal, however, for the Gila monster to be captured or held in the states where it exists. The reptiles can be found in many zoos. (Bogert, 1956) ( http://www.Pharmacy.Arizona.EDU/centers/poison_center/critters/reptiles/gila monster)

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Stewart, M. 2003. "Heloderma suspectum" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Heloderma_suspectum.html
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Trophic Strategy

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The Gila monster's diet consists of a variety of objects: small mammals (young rabbits, mice and squirrels), birds, lizards, and eggs (of birds, lizards, snakes, turtles, and tortoises). The Gila monster has the capability to consume large amounts of food at one time (young can consume 50% of their body weight at a single feeding, adults can consume 35%). This is advantageous in an envirnoment in which finding prey at regular intervals may be difficult. Prey are rarely envenomated, which indicates that venom is used mainly for defense. Prey are detected by olfaction (the sense of smell). The Gila monster, like most snakes, uses its tongue for olfaction. (Ernst, 1992) (Bogert, 1956)

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Stewart, M. 2003. "Heloderma suspectum" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Heloderma_suspectum.html
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Distribution

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The Gila monster ranges from the extreme southwestern Utah, southern Nevada, and adjacent San Bernadino County, California, southeastrward through west and south Arizona and southwestern New Mexico. It ranges south into Mexico through Sonora to northwestern Sinaloa. It ranges from sea level to 1,500 meters in altitude. (Ernst, 1992)

Biogeographic Regions: nearctic (Native )

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Stewart, M. 2003. "Heloderma suspectum" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Heloderma_suspectum.html
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Habitat

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The Gila monster can be found in arid areas. These areas usually contain scattered cacti, shrubs, mesquite, and grasses. Rocky slopes, arroyos, and canyon bottoms (mainly those with streams) support populations in Arizona. (Ernst, 1992)

Terrestrial Biomes: desert or dune

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Stewart, M. 2003. "Heloderma suspectum" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Heloderma_suspectum.html
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Life Expectancy

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Average lifespan
Status: captivity:
8.3 years.

Average lifespan
Status: captivity:
20.0 years.

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Stewart, M. 2003. "Heloderma suspectum" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Heloderma_suspectum.html
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Morphology

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This is one of only two venomous lizard species in the world (the other is the Mexican beaded lizard, Heloderma horridum). Gila monsters are large and stout lizards with a short fat tail (maximum length of 56 centimeters). Their scales are beaded yellow, pink, and black. The broad head, chin, and neck are black, as well as the legs and feet. The black eyes have a round pupil. The ear opening is a narrow oblique or ovoid slit. The limbs of the lizard are stout and have heavy claws. (Ernst, 1992)

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Stewart, M. 2003. "Heloderma suspectum" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Heloderma_suspectum.html
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Reproduction

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Mating, which is usually in May, begins with the male tongue-flicking to seek a females's scent, while rubbing his cloaca on the ground. When a male locates a female, he lies by her and rubs his chin on her back and neck while holding her with his hindlegs. If a female objects to the male, she will try to bite him while crawling out from underneath. If receptive, she raises her tail. The male then moves his tail under hers, bringing their vents into contact. Copulation lasts from 30 minutes to an hour. The female lays her eggs (1-12) in an underground cavity, normally in July or August. Incubation lasts on average about ten months, and the young to hatch and emerge the following May. The process (fertilization through emergence) lasts about a year. (Ernst, 1992)

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Stewart, M. 2003. "Heloderma suspectum" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Heloderma_suspectum.html
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Matthew D. Stewart, University of Michigan-Ann Arbor
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Biology

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As an adaptation to their harsh desert environment, Gila monsters spend a large proportion of their time underground in burrows, hibernating during the winter and sheltering from the midday sun in the scorching summer months. The lizards emerge from hibernation in spring and the majority of their activity occurs in the following three-month period (3). Mating may takes place from April to June (9); males 'wrestle' to assert dominance (3). Females then lay their clutch of up to 12 eggs in late June or August (6). Eggs are laid in depressions dug into the soil and unusually remain incubating underground throughout the winter, hatching the following spring (4). In springtime, Gila monsters are active during the day, although they are mainly above ground in the morning and late afternoon to avoid the midday heat (3). These lizards feed on eggs, young birds and rodents, as well as lizards; juveniles are able to consume over 50% of their body weight at one time (4). Gila monsters are able to survive for months without food as they store fat in their particularly large tail (3). The infamous venomous bite of the Gila monster is used as a defensive measure rather than to attack prey. If threatened, these lizards will back away hissing with their mouth open, and if provoked they attack surprisingly quickly with a bite that can be extremely painful to humans, although it is rarely life-threatening (6).
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Conservation

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Gila monsters are protected throughout their range, first receiving protection in 1952 in Arizona when they were the first venomous reptiles to receive such legislation (6). Over 300 individuals exist in captivity in the United States (8), and with greater understanding of these elusive lizards many of the common myths and superstitions around them have been surmounted (3). It is hoped that conservation measures will allow this a colourful desert-dweller to persist despite its depleted habitat.
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Description

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The Gila monster is the largest lizard in the United States (3), and one of the few species of venomous lizard in the world (4) (5). It has a stocky body with a large head and a short, fat tail (6). The skin consists of many round, bony scales, a feature that was common amongst the dinosaurs but is unusual in today's reptiles (3). Gila monsters have a striking bright pink and black colouration (6) and the two subspecies can be distinguished by their different patterns; the banded Gila monster (Heloderma suspectum cinctum) has a band of light markings along the back whilst in the reticulated Gila monster (H. s. suspectum) these light marks are joined in a network (3). With their venomous bite and elusive nature, these lizards have inspired many myths over the centuries (3).
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Habitat

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Inhabits dry desert scrub and rocky mountain foothills up to 1,500 metres above sea level (3).
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Range

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The majority of the Gila monster's range is in western and southern Arizona, south to southern Sonora in Mexico, although populations are also found in restricted areas of California, Nevada, Utah and New Mexico (6). Of the subspecies, the banded Gila monster occupies the northern extent of the species' range (3). The name 'Gila monster' is derived from the Gila River Basin in Arizona, part of this species' range (4).
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Status

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Classified as Near Threatened (NT) on the IUCN Red List (1).
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Threats

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Much of the bushland of the Gila monster's habitat has been cleared for agriculture and remaining populations are isolated in the resulting fragments that persist (2). Urban development and roads have also encroached on their habitat and many monsters are killed by common feral, or pet, species such as domestic cats and dogs (8). Some specimens are also still illegally collected for the pet trade (7).
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Brief Summary

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The Gila Monster is widely found in the Sonoran Desert. It is the largest lizard found in the United States. The Gila Monster can grow up to 2 feet and weigh more than 5 pounds. It is venomous and carnivorous eating primarily eggs and other newborn mammals. Average life span of the Gila Monster is 20-30 years.

The Gila Monster can be identified by their black bodies with dramatic patterns of orange, pink, or yellow. They were first discovered in Arizona’s Gila Basin where they received their name. They now reside in the Sonoran, Chihuahuan, and Mojave Deserts. But the Gila Monster population is shrinking due to human encroachment, and they are now on the threatened species list.

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Distribution

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Continent: Middle-America North-America
Distribution: USA (SE California, S Nevada, SW Utah, Arizona, New Mexico), Mexico (Sonora)
Type locality: Sierra de la Unión, œSonora (= Arizona)
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Gila monster

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A Gila monster

The Gila monster (Heloderma suspectum, /ˈhlə/ HEE-lə) is a species of venomous lizard native to the Southwestern United States and the northwestern Mexican state of Sonora. A heavy, typically slow-moving lizard, up to 60 cm (2.0 ft) long, the Gila monster is the only venomous lizard native to the United States. Its venomous close relatives, the four beaded lizards (all former subspecies of Heloderma horridum) inhabit Mexico and Guatemala.[2][3] The Gila monster is sluggish in nature, so not generally dangerous and very rarely a real threat to humans. Yet, its exaggeratedly fearsome reputation has led to its sometimes being killed, in spite of being protected by state law in Arizona.[1][4]

History

Evolutionary splitting of the genus Heloderma into species
Evolutionary splitting of the genus Heloderma into species (Reiserer et al)[5]

The name "Gila" refers to the Gila River Basin in the U.S. states of Arizona and New Mexico, where the Gila monster was once plentiful.[6] Heloderma means "studded skin", from the Ancient Greek words helos (ἧλος), "the head of a nail or stud", and derma (δέρμα), "skin". Suspectum comes from the describer, paleontologist Edward Drinker Cope. In the beginning (1857), this new specimen of Heloderma was misidentified and considered to be a northern variation of the beaded lizard already known from Mexico. He suspected the lizard might be venomous due to the grooves in the teeth.[7]

The first drawing of Gila monster from 1857
The first drawing of a Gila monster by Baird, S. F. (1857)[7]

The Gila monster is the largest extant lizard species native to North America north of the Mexican border. Its snout-to-vent length ranges from 26 to 36 cm (10 to 14 in). The tail is about 20% of the body size and the largest specimens may reach 51 to 56 cm (20 to 22 in) in total length. Body mass is typically in the range of 550 to 800 g (1.21 to 1.76 lb). They appear strong in their body structure with a stout snout, massive head, and as "little"-appearing eyes, which can be protected by a nictitating membrane.[8][9][2]

The Gila monster has three close living relatives (the beaded lizards) in Mexico: Heloderma exasperatum, Heloderma horridum and Heloderma alvarezi, as well as another beaded lizard species, Heloderma charlesbogerti, in Guatemala.[2][3]

The evolutionary history of the Helodermatidae may be traced back to the Cretaceous period (145 to 166 million years ago), when Gobiderma pulchrum and Estesia mongolensis have been around. The genus Heloderma has existed since the Miocene, when H. texana lived. Fragments of osteoderms from the Gila monster have been found in Late Pleistocene (10,000 to 8,000 years ago) deposits near Las Vegas, Nevada. Because the helodermatids have remained relatively unchanged morphologically, they are occasionally regarded as living fossils. Although the Gila monster appears closely related to the monitor lizards (varanids) of Africa, Asia, and Australia, their wide geographical separation and unique features not found in the varanids indicate that Heloderma is better placed in a separate family.[10]

The dorsal skin of a Gila monster
The dorsal skin of a Gila monster

Skin

The total molt of a female Gila monster about 2 weeks before egg-laying
The total molt of a female Gila monster about 2 weeks before egg-laying

The scales of the head, back, and tail contain little pearl-shaped bones (osteoderms) similar to the bearded lizards from further south. The scales of the belly are free from osteoderms. Female Gila monsters go through a total shed about 2 weeks before depositing their eggs. The dorsal part is often shed in one large piece. Adult males normally shed in smaller segments in August. The young seem to be in constant shed. Adults have more or less yellow to pink colors on a black surface. Hatchlings have a uniform, simple, and less colorful pattern. This drastically changes within the first 6 months of their lives.[11] Hatchlings from the northern area of the species' distribution have a tendency to retain most of their juvenile pattern.

The heads of males are very often larger and more triangular-shaped than in females. The length of the tail of the two sexes is statistically very similar, so does not help in differentiation of the sexes.[12] Individuals with stout tail ends occur in both nature and under human breeding.

 src=
A plate from the Century Cyclopedia that depicts the Gila monster

Distribution and habitat

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The head of a Gila monster with bead-like scales and strong forelegs and claws suitable for digging

The Gila monster is found in the Southwestern United States and Mexico, a range including Sonora, Arizona, parts of California, Nevada, Utah, and New Mexico. No records have been given from Baja California.[2] They inhabit scrubland, succulent desert, and oak woodland, seeking shelter in burrows, thickets, and under rocks in locations with a favorable microclimate and adequate humidity. Gila monsters depend on water resources, and might be observed in puddles of water after a summer rain. They avoid living in open areas, such as flats and open grasslands.[2]

Ecology

 src=
A Gila monster in captivity

Gila monsters spend 90% of their lifetime underground in burrows or rocky shelters.[2] They are active in the morning during the dry season (spring and early summer). The lizards move to different shelters every 4-5 days up to the beginning of the summer season. By doing so, they optimize for a suitable microhabitat for survival.[2][13][14] Later in the summer, they may be active on warm nights or after a thunderstorm. They maintain a surface body temperature of about 30 °C (86 °F).[2] Close to 37°C, they are able to decrease their body temperature up to 2°C by an activated, limited evaporation via the cloaca.[15] Gila monsters are slow in sprinting ability, but they have relatively high endurance and maximal aerobic capacity (VO2 max) for a lizard.[16] They are preyed upon by coyotes, badgers and raptors. Hatchlings are preyed on by snakes, e.g., kingsnakes (Lampropeltis sp.).

Diet

The Gila monster's diet consists of a variety of food items - small mammals (such as young rabbits, hares, mice, ground squirrels, other rodents, etc.), small birds, snakes,[17] lizards, frogs, insects, carrion, and the eggs of birds, lizards, snakes, and tortoises.[18][19][20][21] Three to four extensive meals in spring are claimed to give them enough energy for a whole season. Nevertheless, they feed whenever they comes across suitable prey. Hatchlings digest their yolk reserve in winter underground for their energy supply and survival.[13] Young can swallow up to 50% of their body weight at a single meal.[15] Adults may eat up to one-third of their body weight in one meal.[8]

This Heloderma sp. uses its extremely acute sense of smell to locate prey. The strong, two-ended tipped tongue is pigmented in black-blue colors,[11] serves as orientation and picks up scent molecules as chemical information to be transferred to the opening of the Jacobson organ around the middle of the upper mouth cavern; information is then immediately transported to the brain to be decoded.

Prey may be crushed to death if large, or eaten alive, most of the time head first, and helped down by muscular contractions and neck flexing. After food has been swallowed, the Gila monster immediately might resume tongue flicking and search behavior for identifying more prey such as eggs or young in nests. Gila monsters are able to climb trees and cacti and even up fairly straight, rough-surfaced walls.[2][22]

Venom

"I have never been called to attend a case of Gila monster bite, and I don't want to be. I think a man who is fool enough to get bitten by a Gila monster ought to die. The creature is so sluggish and slow of movement that the victim of its bite is compelled to help largely in order to get bitten."

–Dr. Ward, Arizona Graphic, September 23, 1899

Pioneer beliefs

In the Old West, the pioneers believed a number of myths about the Gila monster, including that the lizard had foul or toxic breath and that its bite was fatal.[23] The Tombstone Epitaph of Tombstone, Arizona, wrote about a Gila monster that a local person caught on May 14, 1881:

This is a monster, and no baby at that, it being probably the largest specimen ever captured in Arizona. It is 27 inches long and weighs 35 lb. It was caught by H. C. Hiatt on the road between Tombstone and Grand Central Mill, and was purchased by Messrs. Ed Baker and Charles Eastman, who now have it on exhibition at Kelley's Wine House, next door above Grand Hotel, Allen Street. Eastern people who have never seen one of these monsters should not fail to inspect his Aztecship, for they might accidentally stumble upon one some fine day and get badly frightened, except they know what it is.

On May 8, 1890, southeast of Tucson, Arizona Territory, Empire Ranch owner Walter Vail captured and thought he had killed a Gila monster. He tied it to his saddle and it bit the middle finger of his right hand and would not let go. A ranch hand pried open the lizard's mouth with a pocket knife, cut open his finger to stimulate bleeding, and then tied saddle strings around his finger and wrist. They summoned Dr. John C. Handy of Tucson, who took Vail back to Tucson for treatment, but Vail experienced swollen and bleeding glands in his throat for sometime afterward.[23]

Dr. Handy's friend, Dr. George Goodfellow of Tombstone, was among the first to research the actual effects of Gila monster venom. Scientific American reported in 1890, "The breath is very fetid, and its odor can be detected at some little distance from the lizard. It is supposed that this is one way in which the monster catches the insects and small animals which form a part of its food supply—the foul gas overcoming them." Goodfellow offered to pay local residents $5.00 for Gila monster specimens. He bought several and collected more on his own. In 1891, he purposely provoked one of his captive lizards into biting him on his finger. The bite made him ill and he spent the next five days in bed, but he completely recovered. When Scientific American ran another ill-founded report on the lizard's ability to kill people, he wrote in reply and described his own studies and personal experience. He wrote that he knew several people who had been bitten by Gila monsters, but had not died from the bite.[23]

Venom delivery

Venom Grooves and position of the exchange teeth
Venom grooves and position of the exchange teeth
Gila monster Skull showing dentition
Gila monster skull showing dentition (osteoderms are fused with the forehead), photo by A. Laube

The Gila monster produces venom in modified salivary glands at the end of its lower jaws, unlike snakes, whose venom is produced in glands behind the eyes.[24] The Gila monster lacks the strong musculature in glands above the eyes; instead in Heloderma, the venom is propelled from the gland via a tubing to the base of the lower teeth and then by capillary forces into two grooves of the tooth and then chewed into the victim.[2] The teeth are tightly anchored to the jaw (pleurodont). Broken and regular replacement teeth have to wait every time to go into position in a determinate “wavelike” sequence. They change their teeth all their life long.[25][26] The Gila monster's bright colors might be suitable to teach predators not to bother this “painful” creature. Because the Gila monster's prey consists mainly of eggs, small animals, and otherwise "helpless" prey, the Gila monster's venom is thought to have evolved for defensive rather than for hunting use.[27]

Toxicity

The venom of a Gila monster is considered to be as toxic as that of a western diamondback rattlesnake. Milking H. suspectum for its venom it can yield up to 2 ml. The Gila monster's bite is normally not fatal to healthy adult humans.[23] No reports of fatalities have been confirmed after 1930, and the rare fatalities recorded before that time occurred in adults who were intoxicated by alcohol or had mismanaged the treatment of the bite.[28] The Gila monster can bite quickly, and may not release the victim without intervention. If bitten, the victim may attempt to fully submerge the lizard in water, pry the jaws open with a knife or stick, or physically yank the lizard free. While pulling the lizard directly off risks severe lacerations from the lizard's sharp teeth, it may mitigate envenomation. Symptoms of the bite include excruciating pain, edema, and weakness associated with a rapid drop in blood pressure.

One zoological journalist, Coyote Peterson, when giving a report about the pain of a bite, described it as "the worst pain [he] had ever experienced...it's like hot lava coursing through your veins." It is generally regarded as the most painful venom produced by any vertebrate.[29]

More than a dozen peptides and other substances 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, without producing a compartment syndrome. Four potentially lethal toxins have been isolated from the Gila monster's venom, which cause hemorrhage in internal organs and exophthalmos (bulging of the eyes),[30] and helothermine, which causes lethargy, partial paralysis of the limbs, and hypothermia in rats. Some are similar in action of the 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.[31][32]

Toxins and drug research

The constituents of H. suspectum venom that have received the most attention from researchers are the bioactive peptides, including helodermin, helospectin, exendin-3, and exendin-4.[33] Exendin-4, which is specific for H. suspectum, has formed the basis of a class of medications for the treatment of type 2 diabetes, known as Glucagon-like peptide-1 agonists.

In 2005, the U.S. Food and Drug Administration approved the drug exenatide (marketed as Byetta) for the management of type 2 diabetes. It is an extravagantly synthetic blueprint of the protein exendin-4, isolated from the Gila monster's venom.[34][35] In a 3-year study with people with type 2 diabetes, exenatide showed healthy sustained glucose levels. The effectiveness is because the lizard protein is 53% identical to glucagon-like peptide-1 analog (GLP-1), a hormone released from the human digestive tract that helps to regulate insulin and glucagon. Using a sophisticated injection formula with sustained release of the drug the lizard protein remains effective much longer than the human hormone, This helps diabetics keep their blood glucose levels under control for a week by a single injection. Exenatide also slows the emptying of the stomach and causes a decrease in appetite, contributing to weight loss.[36]

Lifecycle

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A Gila monster (H. suspectum)

The Gila monster emerges from brumation* in early March. H. suspectum sexually matures at 4-5 years old. It mates in April and May.[2] 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 chase him away. When successful, copulation has been observed in captivity to last from 15 minutes to two and a half hours. There is only a single record of attempted mating outside of a shelter.[19] The female lays eggs at the end of May into June. A clutch may consist of up to six (rarely up to eight) eggs.[2][11] The incubation in captivity lasts about 5 months, depending on the incubation temperature. The hatchlings are about 16 cm (6.3 in) long and can bite and inject venom as soon as they are hatched.

The egg development and hatching time of young in the wild has been a subject of ongoing speculation. The first model stated that youngsters hatch in fall and stay underground. The second theory postulated a nearly developed embryo remains inside the egg over winter and hatches in spring. Hatchlings (weight about 35 g) are observed at the end of April to early June.

These discussions came to an abrupt, unexpected end on October 28th, 2016, when a backhoe was digging at the outer walls of a house in a suburb of northern Tucson. The backhoe extracted a nest of H. suspectum with five eggs in the process of hatching. The Gila monster is now known to hatch near the end of October and immediately proceed into hibernation without surfacing. [13] They then appear on the surface from May through June the following year when prey should be abundant.

In summer, Gila monsters gradually spend less time on the surface to avoid the hottest part of the season; occasionally, they may be active at night. Females that have laid eggs are exhausted and thin, fighting for survival, and have to spend extra effort to "reconstitute". The brumation of Gila monsters begins in October.[2] Gila monsters can live up to 40 years in captivity, though rarely.

Little is known about the social behavior of H. suspectum, but it has been observed engaging in male to male combat, in which the dominant male lies on top of the subordinate one and pins it with its front and hind limbs. While fighting, 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 exerts their forces, although bouts may be repeated.[27] These bouts are typically observed in the mating season. Males with greater strength and endurance are thought to enjoy greater reproductive success.[2] 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 it to engage in intense aerobic activity for a sustained period of time.

Conservation status

Gila monsters are listed as near threatened by the IUCN.[1]

In 1952, the Gila monster became the first venomous animal to be given legal protection.[37] They are now protected in all states of their distribution. The Gila monsters' international trade is regulated in Appendix II B in the CITES.

Relocation

"Possibly the greatest threat to the continued existence of helodermatids is the man-made destruction of their habitat as the land is developed for construction or to create more cultivable land."[38] Gila monsters found in these situations and relocated – with best intentions – up to 1.2 km away, return to where they were found within 2 months and at great effort. This is up to five times the normal energy use than if they had not been removed, which uses up their energy stores unnecessarily. The same is true for animals relocated to appropriate habitats. Besides this, they also become more exposed to predators. Therefore, the process of simple relocation is "naïve" and potentially dangerous for both the relocated animals and existing populations and for the inhabitants of the region where the resettlement is taking place. If relocating the lizards further away, they might be totally disoriented, thus their survival is still very questionable. A more successful strategy would be, for example, if the new "settlers" were offered intensive education about this species (e.g., limited toxicity, lifestyle) with the aim of tolerating the reptile or even being proud of having this unique "roommate" in one's own neighborhood.[37]

In 1963, the San Diego Zoo became the first zoo to successfully breed Gila monsters in captivity.[39] In the last two decades, experienced breeders have shared their knowledge and expertise to give advice to other herpetologists on overcoming the difficulties in Heloderma reproduction under human care.[11][40][41]

Relationship with humans

Though the Gila monster is venomous, in having laggard movement, it poses little threat to humans. However, it has a fearsome reputation and is often killed by humans. Myths that have formed about the Gila monster include that the animal's breath is toxic enough to kill humans, that it can spit venom like a spitting cobra, that it can leap several feet in the air to attack,[39] and that the Gila monster did not have an anus and therefore expelled waste from its mouth, the source of its venom and "fetid breath" (Note: The venom in fact has an intensive, specific smell).[11]) Among Native American tribes, the Gila monster had a mixed standing. The Apache believed its breath could kill a man, and the Tohono O'Odham and the Pima believed it possessed a spiritual power that could cause sickness. In contrast, the Seri and the Yaqui believed the Gila monster's hide had healing properties.

The Gila monster starred as a monster in the film The Giant Gila Monster (though the titular monster was actually portrayed by a Mexican beaded lizard).[42] It played a minor role in the motion picture The Treasure of the Sierra Madre. In Brock Brower's 1971 novel The Late Great Creature, fictional horror movie star Simon Moro is presented as famous for playing the reptilian werewolf-like Gila Man. The 2011 animated film Rango featured a Gila monster as an Old West outlaw named Bad Bill, voiced by Ray Winstone.[43]

The Gila monster has also seen usage as a mascot and state symbol. The official mascot of Eastern Arizona College located in Thatcher, Arizona, is Gila Hank, a gun-toting, cowboy hat-wearing Gila monster. In 2017, the Vegas Golden Knights selected a Gila monster named Chance as their official mascot.[44] In 2019, the state of Utah made the Gila monster its official state reptile.[45]

Gallery

See also

References

  1. ^ a b c Hammerson, G.A., Frost, D.R. & Gadsden, H. (2007). "Heloderma suspectum". IUCN Red List of Threatened Species. 2007. Retrieved 2021-02-13.CS1 maint: uses authors parameter (link)
  2. ^ a b c d e f g h i j k l m n Beck, D. D. (2005). Biology of Gila monsters and beaded lizards (Vol. 9). University of California Press.
  3. ^ a b Bogert, Charles M.; Rafael Martin del Campo (1956). The Gila Monster and its allies: the relationships, habits, and behavior of the lizards of the Family Helodermatidae. New York: Bulletin of the American Museum of Natural History.CS1 maint: multiple names: authors list (link)
  4. ^ "Heloderma suspectum". Integrated Taxonomic Information System. Retrieved 19 May 2008.
  5. ^ R. S. Reiserer, G. W. Schuett, D. D. Beck (2013). "Taxonomic Reassessment and conversation status of the beaded lizard, Heloderma horridum (Squamata Helodermatidae)". Amphibian & Reptile Conservation. 7: 74–96.CS1 maint: multiple names: authors list (link)
  6. ^ "Online Etymology Dictionary". Retrieved 2008-06-10.
  7. ^ a b Baird, S. F. (1859). "Reptiles of the boundary, with notes by the naturalists on the survey". United States and Mexican Boundary Survey Under the Order of Lieut. Col. W.H. Emory. 3: 1–35.
  8. ^ a b Christel CM, DeNardo DF, Secor SM (October 2007). "Metabolic and digestive response to food ingestion in a binge-feeding lizard, the Gila monster (Heloderma suspectum)". Journal of Experimental Biology. 210 (19): 3430–9. doi:10.1242/jeb.004820. PMID 17872997.CS1 maint: uses authors parameter (link)
  9. ^ Davis, Jon R.; DeNardo, Dale F. (2010). "Seasonal patterns of body condition, hydration state, and activity of Gila monsters (Heloderma suspectum) at a Sonoran Desert site". Journal of Herpetology. 44 (1): 83–93. doi:10.1670/08-263.1. S2CID 6808861.
  10. ^ Mattison, Chris (1998). Lizards of the World. London: Blandford. ISBN 0-7137-2357-2.
  11. ^ a b c d e Schwandt, Hans-Joachim (2019). The Gila Monster – Heloderma suspectum. Frankfurt / Main: Edition Chimaira. ISBN 978-3-89973-441-6.
  12. ^ Gienger, C. M. and Beck, Daniel D (2007). "Heads or tails? Sexual dimorphism in helodermatid lizards". Canadian Journal of Zoology. 85: 92–95. doi:10.1139/z06-198.CS1 maint: multiple names: authors list (link)
  13. ^ a b c DeNardo, DF; Moeller, KT; Seward, M; Repp, R. (2018). "Evidence for atypical nest overwintering by hatchling lizards, Heloderma suspectum". Proceedings of the Royal Society. 285 (1879). doi:10.1098/rspb.2018.0632.
  14. ^ Beck, D.D.; Jennings, R.D. (2003). "Habitat use by Gila Monsters. The importance of shelters". Herpetological Monographs. 17: 112–130. doi:10.1655/0733-1347(2003)017[0111:HUBGMT]2.0.CO;2.
  15. ^ a b DeNardo, Dale F.; Zubal, Tricia E.; Hoffman, Ty C. M. (2004). "Cloacal evaporative cooling: a previously undescribed means of increasing evaporative water loss at higher temperatures in a desert ectotherm, the Gila monster Heloderma suspectum". The Journal of Experimental Biology. 207 (Pt 6): 945–953. doi:10.1242/jeb.00861. PMID 14766953.
  16. ^ Beck, D. D.; Dohm, M. R.; Garland, Jr., T.; Ramirez-Bautista, A.; Lowe, C. H. (1985). "Locomotor performance and activity energetics of helodermatid lizards". Copeia. 1995 (3): 577–585. doi:10.2307/1446755. JSTOR 1446755.
  17. ^ https://a-z-animals.com/animals/gila-monster/
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  23. ^ a b c d Lapidus, Richard (June 3, 2011). "The Gila Monster Had a Killer Reputation". Wild West Magazine. Retrieved 10 March 2013. Although the Gila monster's bite is extremely painful, none has resulted in a verifiable human fatality to a healthy person.
  24. ^ West, G. S. (1895). "On the Buceal-Glands and Teeth of certain poisonous Snakes". Proceed. Zool. Soc. Of London.
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  27. ^ a b Beck, Daniel D. (1990). "Ecology and behavior of the Gila monster in southwestern Utah". Journal of Herpology. 24–1: 54–58. doi:10.2307/1564290. JSTOR 1564290.
  28. ^ Strimple, Peter D.; Tomassoni, Anthony J.; Otten, Edward J.; Bahner, David (1997). "Report on envenomation by a Gila monster (Heloderma suspectum) with a discussion of venom apparatus, clinical findings, and treatment". Wilderness & Environmental Medicine. 8 (2): 111–116. doi:10.1580/1080-6032(1997)008[0111:ROEBAG]2.3.CO;2. ISSN 1080-6032. PMID 11990142.
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  30. ^ POISINDEX(R) TOXICOLOGIC MANAGEMENTS: Topic: GILA MONSTER (HELODERMA SUSPECTUM)
  31. ^ Maruno K, Said SI (1993). "Small-cell lung carcinoma: inhibition of proliferation by vasoactive intestinal peptide and helodermin and enhancement of inhibition by anti-bombesin antibody". Life Sciences. 52 (24): PL267–71. doi:10.1016/0024-3205(93)90640-O. PMID 8389407.
  32. ^ Clarke, Toni. "Gila Monster Spit May Yield Alzheimer's Drug". Retrieved 2011-05-29.
  33. ^ Aird SD (June 2008). "Nucleoside composition of Heloderma venoms". Comparative Biochemistry and Physiology B, Biochemistry and Molecular Biology. 150 (2): 183–6. doi:10.1016/j.cbpb.2008.02.012. PMID 18430599.
  34. ^ Bond, Aaron (July 2006). "Exenatide (Byetta) as a novel treatment option for type 2 diabetes mellitus". Baylor University Medical Center Proceedings. 19 (3): 281–4. doi:10.1080/08998280.2006.11928181. PMC 1484540. PMID 17252050.
  35. ^ Chen, Tianbao, H.K. Kwok, C. Ivanyi, Cristipher Shae (2006). "Isolation and cloning of exendin precursor cDNAs from single samples of venom from the Mexican beaded lizard (Heloderma horridum) and the Gila monster (Heloderma suspectum)". Toxicon. 47–3 (3): 288–295. doi:10.1016/j.toxicon.2005.11.004.CS1 maint: multiple names: authors list (link)
  36. ^ "Drug Derived From Gila Monster Saliva Helps Diabetics Control Glucose, Lose Weight". Science Daily. 2007-07-12.
  37. ^ a b Sullivan, Brian K., Kwiatkowski, Matthew A., Schuett, Gordon W. (2004). "Translocation of urban Gila Monsters: a problematic conservation tool". Biological Conservation. 117 (3): 235–242. doi:10.1016/j.biocon.2003.07.002.CS1 maint: multiple names: authors list (link)
  38. ^ Repp, Roger A. (2017). "A Monstrous Helloween Treat". Bulletin of the Chicago Herpetological Society. 52 (2): 28–35.
  39. ^ a b "San Diego Zoo's Animal Bytes: Gila Monster". San Diego Zoo. Retrieved 2008-05-19.
  40. ^ Seward, Mark (2002). Dr. Mark Seward's Gila monster Propagation: How To Breed Gila monsters in Captivity. Natural Selections Publishing. p. 80. ISBN 0-9701395-0-0.
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  42. ^ "Gila Monsters And Beaded Lizards". Reptiles Magazine. 2011-12-01. Retrieved 2021-01-08.
  43. ^ Coyle, Jake (March 4, 2011). "Movie review: 'Rango'". Associated Press via NorthJersey.com. Archived from the original on March 8, 2011.
  44. ^ "Vegas Golden Knights reveal Chance as team's mascot". Las Vegas Review-Journal. October 13, 2017. Retrieved 1 May 2018.
  45. ^ "HB0144". le.utah.gov. Retrieved 2019-05-15.
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Gila monster: Brief Summary

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A Gila monster

The Gila monster (Heloderma suspectum, /ˈhiːlə/ HEE-lə) is a species of venomous lizard native to the Southwestern United States and the northwestern Mexican state of Sonora. A heavy, typically slow-moving lizard, up to 60 cm (2.0 ft) long, the Gila monster is the only venomous lizard native to the United States. Its venomous close relatives, the four beaded lizards (all former subspecies of Heloderma horridum) inhabit Mexico and Guatemala. The Gila monster is sluggish in nature, so not generally dangerous and very rarely a real threat to humans. Yet, its exaggeratedly fearsome reputation has led to its sometimes being killed, in spite of being protected by state law in Arizona.

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