San Diego Natural History Museum--Your Nature ConnectionSDNHM Field Guide
Colorado Desert Sidewinder, photographed by Dick Schwenkmeyer

Crotalus cerastes


Crotalus comes from the Greek crotalon, a rattle or little bell; cerastes means horned, referring to the horns above its eyes.


The Sidewinder is the smallest rattlesnake of our region, and rarely measures more than 2 feet in length.

The coloration of this small rattlesnake matches the pale tans and pinks of the sand where it lives. Its back is patterned with small, dark, square-shaped blotches. A dark stripe extends from the outer corner of the eye to the corner of the mouth. A horn-like process protrudes over the eye, in North America, this feature is unique to the Sidewinder.

Subspecies: Three subspecies have been recognized: Mojave Desert Sidewinder (C. c. cerastes); the Sonoran Sidewinder (C. c. cercobombus); and the Colorado Desert Sidewinder (C. c. laterorepens).

Only the Colorado Desert Sidewinder occurs in this region and was described (named) by noted San Diego herpetologist Laurence M. Klauber.


The Sidewinder range extends through the sandy desert habitats of southern Nevada, to northeastern Baja California and northern Sonora, Mexico, east into central Arizona, and west to the base of the desert side of California's mountains. This distribution mirrors the combined Mojave and Sonoran Deserts. The Colorado Desert Sidewinder (C. c. laterorepens) inhabits the deserts of our region, east of the mountains, from Palm Springs to northeastern Baja and western Sonora in Mexico.

Natural History

All snakes lack eyelids and are unable to blink or close them. The enlarged horns of Sidewinders, located above the eyes, serve as a mechanism that allows the eyes to "close." When burrowing, the pressure exerted on the top of the horns push the base of the scale downward and covers the eye. This protects it from being scratched.

Early in the spring the Sidewinder may be active during the day, but as soon as the weather warms up, it becomes nocturnal. It's strictly a desert creature, specially adapted for life in wind-blown sand. Sidewinding is an adaptation for moving over soft sand. When sidewinding, the snake applies vertical pressure to the ground which minimizes slippage, and leaves a distinctive parallel series of "J" shaped tracks. The hooks of the "J" marks point in the direction of travel.

Did you know...

Sidewinders can travel in the serpentine mode (the usual snaky method) if they have to, for example, to turn a sharp corner.

Conservation Status

There have been no proposed conservation plans. Because of widespread negative attitudes towards snakes, very few conservation programs, worldwide, have been created. A much higher percentage of snakes are threatened with extinction than is currently recognized. Therefore, snakes are particularly susceptible to being overlooked by conservation-minded biologists.

Text by Jim Melli and Brad Hollingsworth.
Photo by Dick Schwenkmeyer.

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