Gila Monster

ORDER: Squamata

FAMILY: Helodermatidae

GENUS: Heloderma

SPECIES: suspectum

A gaudily patterned lizard that has brightly colored bead like scales on its back. The coloration of the skin is black with contrasting pink, yellow or orange. This is a heavy-bodied lizard that has a short, stout tail that stores fat it can live off of during periods of food shortage. Their size ranges from 17.75 to 24 inches.

Southwest US: S. Utah, Arizona to New Mexico; Mexico. They live in semi desert or scrub with rocky outcrops, in places where there is ready access to moisture. They are found under rocks, in burrows of other animals,sometimes in holes it digs itself.

Carnivorous. Small mammals, lizards, frogs, insects, carrion, birds and birds' eggs.

These lizards mate during the summer, and the female lays her clutch of 3 to 5 eggs about 5 inches below the surface some time later, in the autumn or winter. In about 117-130 days, the eggs hatch. The vibrantly-colored babies are about 4 inches in length at the time of hatching. They can live up to 20 years in captivity.

The Gila monster is one of only two venomous lizards, the other being the Mexican beaded lizard. Venom is produced in glands in the lower jaw, not the upper jaw as in snakes. The poison is not injected but flows into the open wound as the lizard uses its powerful jaws to chew on its victim. Its bite, although painful, is not usually fatal for adult humans.

Compared to most other lizards, they are slow moving, hunting by day in the spring and at dusk or after dark during the summer heat. They seem to rely more on taste and smell to locate their prey rather than vision. They hibernate during the cold weather

The Gila Monsters can be found in the RAD Room in the Wayne and Gladys Valley Children's Zoo.

Vulnerable. Species not presently threatened, but may become so unless trade is regulated. On Appendix II of CITES. Listed as Near Threatened by IUCN.


  1. Burnie, David and Wilson, Don 2001. Smithsonian Institution ANIMAL, DK Publishing, New York, p. 419.
  2. Knopf, Alfred 1998. National Audubon Society Field Guide to North American Reptiles and Amphibians, Chanticleer Press, Inc., New York, p. 546.
  3. Whitfield, Philip 1998. Encyclopedia of Animals, Simon & Schuster Editions, New York, p.449.