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Gila Monster

The Gila Monster is a large fat lizard with a large head, tiny eyes and a fat stumpy tail. The color is usually a mottled blend of orange or pink and black. It is a member of the beaded lizard family, a name which refers to the bumpy appearance of its skin.

Natural History

Gila Monsters are mainly found in western and southern Arizona and in Mexico, though they are more rarely spotted in a few of the other states in the desert southwest. They prefer mountain foothills and washes where saguaros and polo verde trees are found. They typically occupy two different burrows during the course of the year that they either constructed themselves or took over from another animal; a winter burrow that they will hibernate in from November through February and a summer burrow, usually near a wash and a source of food.

Gila Monsters are one of only two species of venomous lizards in the world (it's cousin the Mexican Beaded Lizard is the other).

Gila Monsters eat small or newborn mammals, but will also prey on birds and lizards as well as their eggs. They eat a lot for their size and can consume as much as 35% of their body weight in one meal. They usually breed in spring, and females lay eggs during the summer. The eggs incubate and develop all winter and the young hatch the following spring (a trait unique among North American lizards).


Gila Monsters produce venom in glands in their lower jaw. Rather than injecting venom through hollow fangs like venomous snakes, Gilas have enlarged, grooved teeth in their lower jaw. When they bite, their powerful jaws chew the venom in through capillary action along the grooves in these teeth. The venom of this lizard is thought to be a defensive weapon since it probably doesn't need it to catch and consume its prey.

"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, 1899

The bite is rarely life threatening to humans, but may cause: pain, edema, bleeding, nausea and vomiting. Gila Monsters are protected in the United States. It is illegal to collect, kill, or sell them in Arizona.

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