Gila Monster (Heloderma suspectum) 14" long (largest native lizard in US)

Talk about bad press! How'd you like to have "Monster" as your last name?

Gila monster

This unjustly maligned lizard is a native of Arizona, New Mexico and southern Utah. Its orange, yellow or pinkish body is covered with black beadlike scales in bands or reticulations. The photo below demonstrates what good camouflage this is when viewed against the natural habitat of the animal. The belly scales are flat and rectangular, the snout and sides of the face, usually black.

Gila monster camouflage

The Gila Monster is the largest lizard in the United States and can be up to twenty inches in length and two pounds in weight, though generally they are about 14 inches long. It has a large head, round body and short legs. This slow-moving, sluggish lizard feeds mainly on insects and the eggs of birds and lizards, which it obtains by raiding nests. It stores nutritional fat in its tail, so the tail can be either plump and rounded or short and shriveled up, depending on the season and the health of the animal. Four or five good meals allow it to store up enough fat to live for a year underground or in a rock crevice. These lizards are fairly numerous in their proper habitat but are seldom seen because they spend 90% of their time underground, coming out mainly in spring or during the summer monsoons. They may appear during the day in spring and fall, or at night in summer. Winter activity is generally limited to basking on sunny rocks. Gila Monsters have lived as long as twenty-five years in captivity.

A Gila Monster will avoid interaction with humans if given a chance. The photo below shows a threat display that is a warning to Keep Away! This lizard is not generally aggressive and attacks only when persistently irritated by being picked up or cornered. When it does bite, it bites hard and hangs on with bulldog tenacity. Its poison glands are in the posterior lower jaw, and it cannot inject its venom as a snake does. It needs to bite and chew to break the skin so venom is absorbed.

Gila monster warning behavior

If you are bitten by a Gila Monster the most important thing is to remove the lizard as quickly as possible, which is not necessarily an easy thing. If you have water available a good tactic is to submerge the animal so that it will release its grip in order to breathe. Other remedies include wrapping a towel or shirt around the animal's head to frighten it into releasing the bite. If all else fails, use a stick to pry the jaws open. Symptoms of Gila Monster bite include pain, bleeding, swelling, and low blood pressure. Anyone bitten by a Gila Monster should seek medical attention as soon as possible to clean and evaluate the wound which may have teeth imbedded in it. A tetanus shot will probably be advised.

NOTE: The Gila Monster is the first venomous reptile to be protected in the U.S. It is illegal to handle, collect, or kill a Gila Monster throughout its range in the U.S. and Mexico.

Recommended reading:

Brennan, Thomas C. and Andrew T. Holycross. A Field Guide to Amphibians and Reptiles in Arizona. Phoenix: Arizona Game and Fish Department, 2006.

Hare, Trevor. Poisonous Dwellers of the Desert: Description, Habitat, Prevention, Treatment Tucson: Southwest Parks and Monuments Association, 1995. A short, reasonably priced guide to venomous desert life--how to avoid getting bit and what to do if you do, illustrated by Barbara Terkanian.

Larson, Peggy Pickering. The Deserts of the Southwest: A Sierra Club Naturalist's Guide (Sierra Club Naturalist's Guides) 2nd edition. San Francisco: Sierra Club Books, 2000.