The Gila monster (Heloderma suspectum) is a species of lizard that was once thought to be one of only two species of venomous lizards. (The other is the Mexican beaded lizard.) The Gila (pronounced ) monster lives in the deserts of the southwestern USA and northwestern Mexico. It is a heavy, slow moving lizard, up to 60 cm (2 feet) long. Its skin has the appearance of beads in the colors black, pink, orange, and yellow, laid down in intricate patterns.

It was thought to be one of only two venomous lizards, but recent discoveries have shown that iguanas and monitor lizards also produce venom. Unlike snakes who use hollow teeth (fangs), the Gila monster injects venom into its victim through grooves in the teeth of its lower jaw. It produces only small quantities of its neurotoxic venom, which is secreted into the lizard's saliva. By chewing its prey, however, it tries to put as much of the poison into the bloodstream of its victim as possible.

The Gila monster's bite is normally not fatal to humans (there are no reliable reports of fatalities), but it can bite quickly and holds on tenaciously.

The Gila monster's diet generally consists of small rodents, juvenile birds as well as eggs of both birds and reptiles. They have few natural predators of their own.

The name "Gila monster" refers to the Gila River Basin in Arizona.

In 2005 the Food and Drug Administration of the United States approved a drug for the management of Type 2 diabetes, Byetta (exenatide), a synthetic version of a protein derived from the Gila monster's saliva. The drug is sometimes referred to, with amusement, as 'lizard spit'.

Subspecies

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There exist two subspecies.

• Heloderma suspectum cinctum, the banded Gila monster
• Heloderma suspectum suspectum, the reticulate Gila monster

Conservation status

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Gila monsters are a protected species under Arizona state law in the United States, and may not be collected, killed, or kept in captivity without a permit in that state. They are listed as a threatened species under the United States Federal Endangered Species Act, as well as in Mexico. They also appear in Appendix II of CITES, which puts restrictions on their export. The main threat to the species is human encroachment and habitat destruction.^*

Morphology of the skeleton

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View 3D computed tomographic (CT) animations of the skeleton of adult and juvenile Gila monsters at DigiMorph.org

References

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• Listed as Vulnerable (VU A2cd v2.3)

External links

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• ARKive - images and movies of the Gila monster (Heloderma suspectum)
• Heloderma information, list serve, photos and more
• Medical use of Gila monster venom

Helodermas | Fauna of Mexico | Fauna of the Sonoran Desert | Fauna of the United States | Venomous animals

Gila-Krustenechse | Heloderma suspectum | Gila monster | Monstro-de-gila | Gilalisko