Which venomous lizard is native to the southwestern United States?

The venomous lizard native to the southwestern United States is the Gila monster. Its scientific name is Heloderma suspectum, and it is the only venomous lizard native to the United States.

Gila monsters occur mainly in Arizona, New Mexico, Nevada, Utah, and parts of California, as well as in the Mexican state of Sonora. The name “Gila” comes from the Gila River Basin, where the animal was once common. Its bright orange-and-black or pink-and-black pattern warns potential predators to keep their distance.

Unlike snakes, which inject venom through specialized fangs, a Gila monster releases venom from glands in its lower jaw. Grooved teeth and a powerful bite allow the venom to flow into a wound as the lizard chews. The bite is extremely painful, although the species is slow-moving and generally avoids people.

Mexican and beaded lizards are close venomous relatives, but they are not the canonical answer to this question. They are associated mainly with Mexico and Guatemala, whereas the Gila monster is the distinctive venomous lizard of the American Southwest.