Chuckwallas are large lizards of the iguana family that live in the Western US and Mexico. They are wide, wrinkly lizards, looking like an iguana that has overeating and avoiding exercise for a good long while. The prefer rocky areas, deserts, and coastal islands, and are well known in Sonoran desert, Mojave Desert, and the Baja peninsula.
Chuckwallas are herbivorous, although they also eat insects when they come across them. They are harmless, and will probably run if they see a human. They hide in rock crevices, and inflate their bodies so that predators can't pull them out of their hiding places.
They are diurnal, and are so well adapted to the desert heat that they will hibernate through the colder months, emerging around February.
The name Chuckwalla comes from the Shoshone Indian word tcaxxwal or the related Cahuilla Indian word caxwal, interpreted by Spaniards as chacahuala, and finally settling into the current American spelling.