Common Chuckwalla
Common Chuckwalla

Sauromalus ater - (Duméril, 1856)

Order: Squamata
    suborder: Lacertilia
                family: Iguanidae
"Chuckwallas were seen perching on rocks so hot as to be unbearable to the hand, and big, gorgeously colored males were noted in pursuit of each other over the hillsides in the middle of the hottest July days."
taken from the notes of Mr. Camp
as quoted in 1922 by John Van Denburgh

The second largest lizard in our area, the Chuckwalla is a heavy-bodied prehistoric looking lizard that inhabits the rocky slopes of the desert. Aptly named, Sauromalus is derived from the Greek words sauros meaning lizard and homalos meaning flat. Until recently the species was named obesus which is Latin for fat or swollen. In 1998 Hollingsworth synonymized two forms and the valid name is now Sauromalus ater.


Adult range from 16" to 21" TTL, males usually larger.


The Chuckwalla is a curious lizard whose body is covered by small coarse scales which give it a sandpaper-like feel. Folds of skin on the neck and sides of the body in conjunction with the rough hide of the chuckwalla serve to assist the lizard in its primary method of avoiding predation, which consists of wedging itself in a rock crevice and then inflating itself to further prevent a predator from successfully extracting it. Strong limbs and a triangular head as wide as it is long give an intimidating aura to this surprisingly herbivorous lizard. The Chuckwalla’s coarse stout tail facilitates a secondary defense mechanism, somewhat common in larger lizards, tail whipping.

Chuckwallas are a dark colored lizard with black dominating the head and limbs while the body may be speckled grey, burnt orange or solid black. Young are grey to brown and are banded on body and tail with a line of black running across each side of the head. Females often retain this banding, though it may fade with age and in some populations they may become completely speckled having a granite-like appearance. In mature males the banding is completely lost. In the extreme southern part of our range males are solid black with a clean bar of creamy white encircling the abdomen.

Natural History Notes:

Rarely straying far from its rocky retreat and quick to disappear down a crevice at the slightest sign of danger, Chuckwallas are an impressive member of the herpetofauna of southern California that thrive in the heat of the Mojave and Sonoran desert. Often found basking when the heat has driven other lizards for cover, Chuckwallas are able to withstand all but the hottest hours of the hottest summer days.

Look for the large dark heads peering from the top of large rocks on the slopes of boulder strewn slopes. Often they will drop down a crevice when approached even at great distances. Binoculars and a little patience will prove very useful in the late morning to early afternoon hours on most any rock dominated area. Chuckwallas, though rarely seen by the general public are locally abundant throughout their range, and are often found along with Desert Tortoises, Collared Lizards, Spiny Lizards, and Banded Rock Lizards to the south. Nocturnal cohabitants include; Lyre Snakes, Rosy Boas, Kingsnakes, and geckos.

Similar Species:

Chuckwallas are a unique species in the Mojave and Sonoran Deserts and are easily distinguished by their large size and rotund body shape.

Other Photos:

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