The stocky Chuckwalla (Sauromalus obesus) is one of my all-time favorite lizards. Years ago, I and others found it a quite difficult captive, as little was known of its high UVB requirements. Today, however, its husbandry is well-understood, and captive bred animals are readily available.
Food and hot basking sites are the focal points of the Chuckwalla’s life – provide it with each in proper form and you’ll find yourself with a most responsive and interesting pet. Most take quickly to hand feeding, and their vegetable-dominated diet is a plus for many herp enthusiasts.
The body is squat with loose skin folds along the neck and sides, and is colored reddish to light gray with a pale yellow tail. The head, chest and limbs of males are usually black, but some sport very impressive red coloration. Females and young animals (and, for some reason, males in SW Utah) are marked with dark bars.
Adult size varies from 6-18 inches, depending upon location and subspecies. Among lizards native to the USA, large adults are exceeded in size only by the Gila Monster (Heloderma horridum).
Chuckwallas belong to the Family Iguanidae which, as originally conceived, contained over 700 species. Recent taxonomic revisions have left the family with 36 species. S. obesus and S. ater are considered to be the same species by some taxonomists.
“Chuckwalla” is derived from the word caxwal, the name given the lizard by the Cahuilla People and which was later recorded by the Spanish as chacahuala.
The most commonly available species, Sauromalus obesus, inhabits southwestern North America, within the Mojave and Sonoran Deserts and surrouning areas. It ranges from California through southern Nevada, southern Utah, western Arizona and northern Mexico (Baja California and western Sonora). Four subspecies are recognized.
Five additional species of Chuckwalla occur in Mexico and on several islands in the Gulf of California.
Chuckwallas are quite specific in their habitat requirements, being limited to rocky areas within deserts. Lava flows, rock piles, outcroppings and rocky hillsides are typical Chuckwalla habitat, and in undisturbed sites may support large populations. They are diurnal and rely upon rocks for basking and to facilitate their unique escape behavior (please see Part II of this article for details).
Excellent photos of Chuckwallas and their habitat, as well as further natural history information, are posted here.
A very good video showing wild Chuckwallas and their defensive behavior is posted here.
Chuckwalla and juvenile Chuckwalla images referenced from wikipedia and originally posted by Azhikerdude