SPECIES NAMECrotalus atrox
RISK TO HUMANSHighly venomous


Western Diamond-backed Rattlesnake Range Map

Western Diamond-Backed Rattlesnake Activity Chart

California’s largest and most aggressive rattlesnake. Coloration varies from gray, tan/brown, olive-green, to yellowish. Patterns consist of diamond shaped blotches on the dorsal surface that are brown or black in color with light edges. Blotches and patterns can be indefinite resulting in an overall dusty appearance. Broad black and white rings, equal in size, circle the tail with a black ring adjacent to the rattle. Due to the resemblance of a raccoon tail, they are often referred to as “coontail” rattlesnakes. One light stripe extends from behind the eye diagonally to the upper lip to the end of the jaw crossing over the lip. This is the largest rattlesnake in California with adult lengths ranging between 30 to 90 inches.

Range is limited to the southeast corner of California in Imperial, San Bernardino, and Riverside counties. Inhabits arid and semiarid areas including plains and mountains, woodlands and pine forests, deserts, canyons and rocky vegetated foothills. May also be found in areas of the desert that have been modified by urban development and agriculture.

Specializes in small mammals such as mice, rats, rabbits, and gophers. Secondary prey includes ground dwelling birds, lizards, and other small animals. Juveniles will occasionally eat large insects and frogs.

Typically quick to act defensively if startled and will aggressively hold their ground by raising their head high in a striking coil with the tail elevated and rattling, while hissing loudly. May strike and bite if provoked. Primarily active during early daytime hours when temperatures are cool to moderate, often basking in open areas; and seeking shelter in excessive daytime heat. May stay active into the evenings past midnight on warm nights and are not active during cooler periods of winter. Species is most active in mid-March to October. Mating occurs in the spring; 4-25 live young are born between August and October. Neonates measure approximately 10 inches at birth, but can range anywhere from 6-12 inches.