California Reptiles & Amphibians

Sauromalus ater - Common Chuckwalla

Click on a picture for a larger view

Range in California: Red

Adult male, San Diego County

Adult, San Diego County

Adult male, San Diego County

Adult, San Diego County

Adult male, San Diego County

Adult male from lava fields in San Bernardino County © Patrick Briggs

Adult male with adult female, from lava fields in San Bernardino County
© Patrick Briggs

Adult, Antelope Valley, Los Angeles County © Todd Battey

Adult, emerging from rock crevice, San Bernardino County
© 2005 Joshua C. Pace

Adult male in a typical pose on top of a large rock pile, San Diego County

Adult, San Bernardino County
© Loren Prins

Adult male in typical basking poisition, Imperial County

Juvenile, Riverside County
© Jeremiah Easter

A threatened Chuckwalla typically runs into a crack in a rock and inflates itself with air, making it difficult for a predator to pull him out. The tool shown above - a sharpened stone attached to a stick - was used by Native Americans to puncture the skin of an inflated Chuckwalla in order to deflate it, then pull the deflated lizard from the crack. The Chuckwalla was later cooked and eaten.
Courtesy of the Death Valley National Park Visitor Center.

Adult, Inyo County

Todd Battey took these pictures in the Coso Range in southern Inyo County, an area known for its extensive Native American pictographs by the Piute tribe. The large rock contains paintings of deer and bighorn sheep on one side, and human-like forms on the other, including what looks to be a large lizard (the painting is 1.5 feet long) which is certainly a Chuckwalla, considering the importance of this large lizard to these desert inhabitants.

Habitat, San Diego County

Habitat, Imperial County

Habitat, San Diego County

Habitat, San Bernardino County, with a distant Chuckwalla sitting on top of the rock pile in the center of the picture.

Habitat, Riverside County

Artificial riprap habitat, Imperial County

Short Videos

A Chuckwalla emerges from its crack and does a territorial push-up display.

From a wide view of its habtat, we zoom in on a Chuckwalla high on top of a rock.

There are more pictures of this species and its habitat on our Southwest and Baja California pages.

Description

Size

5 - 9 inches long from snout to vent (12.7 - 22.8 cm). (Stebbins 2003) The second largest lizard native to the United States (after the Gila Monster).

Appearance

A large, flat-bodied lizard with a large rounded belly, and a wide-based blunt-tipped tail. The neck and sides of the body are covered with loose folds of skin. Scales are small and granular. Tail will regenerate if detached. Males have enlarged femoral pores.

Color can be black, reddish, gray, brown, yellow, or tan. Several color patterns occur. Color changes with age and varies with the color of the habitat. Some individuals have red torsos. Males have dark, usually black, head, chest, and limbs, with red, black, or yellowish backs. Sometimes the dark coloring is covered with light spots and flecks. The tail and sides are light gray or cream, sometimes reddish. The body and tail of young chuckwallas are more prominently banded with dark and yellow coloring. Females usually retain some of the juvenile body and tail banding.

Behavior & Natural History

Diurnal. Rock-dwelling, sheltering in rock crevices or under rocks. Rocks, especially large outcrops and boulder piles, are used for basking. Chuckwallas are often seen in the morning basking on a large rock pile. After basking, they leave the rocks to forage for food.

Most active from spring through fall, remaining inactive in deep rock crevices during the cold of winter, but may be active all year in warmer areas. Also retreats into rock crevices during extreme heat.

When disturbed, a chukwalla will retreat into a rock crevice and inflate with air to enlarge the body, tightly wedging it in the crack, and making extraction difficult to impossible. Capable of biting hard.

Diet

Eats a variety of vegetation, especially creosote flowers, leaves, fruit, and occasionally insects.

Reproduction

Breeds from April to June. 5 -16 eggs are laid from June to August. Females may only lay eggs every two or three years.

Range

Widely distributed throughout the Mojave and Colorado deserts in California, from the desert slopes of the mountains, north through the Owens Valley and east to the Colorado River. Ranges south into Baja California, and east into southern Nevada and Utah, through eastern Arizona and south into Sonora, Mexico. Sea level to around 6,000 ft. (1,800 m).

Habitat

Inhabits rocky flats and hillsides, lava flows, and large outcrops in the California Mojave and Colorado deserts. Creosote bush is found throughout most of its range. Although primarily associated with natural rock piles, Chuckwallas have also been observed inhabiting atypical places such as burrows in dirt, piles of railroad ties, and artificial rip rap.

Taxonomic Notes

In 1998 Hollingsworth (Herpetological Monographs 12: 38-191) changed the name from S. obesus to S. ater. The name S. obesus is still preferred by many researchers. Look at this CNAH page to read about some of the controversy.

Conservation Issues (Conservation Status)

None.

Taxonomy
Family	Iguanidae	Iguanian Lizards
Genus	Sauromalus	Chuckwallas
Species	ater	Common Chuckwalla
Original Description
Sauromalus - Dumeril, 1856 - Arch. Mus. Hist. Nat. Paris, Vol. 8, p. 535 Sauromalus obesus - Baird, 1858 - Proc. Acad. Nat. Sci. Philadelphia, Vol. 10, p. 253 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Sauromalus - Greek - sauros - lizard and homalos - level or flat - refers to the ability to flatten its body ater - ? from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
Sauromalus obesus - Chuckwalla Formerly called Sauromalus obesus obesus - Western Chuckwalla
Related or Similar California Lizards
None. Sometimes confused for Gila Monsters, but the differences are obvious on close inspection.
More Information and References
Natureserve Explorer California Dept. of Fish and Game Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003. Behler, John L., & F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992. Smith, Hobart M. Handbook of Lizards, Lizards of the United States and of Canada. Cornell University Press, 1946.

Conservation Status
The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game. This common species is on the Special Animals List for some mysterious reason. There are no indications from the list that it is threatened in any way. In 2007, this lizard was legally collectable with a license.
Organization	Status Listing
U.S. Endangered Species Act (ESA)	None
California Endangered Species Act (CESA)	None
California Department of Fish and Game	None
Bureau of Land Management	None
USDA Forest Service	None
Natureserve Global Conservation Status Ranks	G5	Secure
World Conservation Union - IUCN Red List	None