Family: Viperidae, Pit Vipers view all from this family

Description 17-32 3/8" (43.1-82.4 cm). A rough-scaled rattler with a prominent triangular, hornlike projection over each eye. Scales keeled, in 21-23 rows.

Warning Rattlesnakes, Copperheads, and Cottonmouths belong to a group of snakes known as pit vipers. These dangerous snakes have a heat-sensitive sensory organ on each side of the head that enables them to locate warm-blooded prey and strike accurately, even in the dark. The curved, hollow fangs are normally folded back along the jaw. When a pit viper strikes, the fangs rapidly swing forward and fill with venom as the mouth opens. The venom is a complex mixture of proteins that acts primarily on a victim's blood tissue. If you hear a rattlesnake shaking its rattle, back away. The snake is issuing a warning, and if the warning is ignored it may bite. There are many factors (temperature being the most important) that determine how a snake will react when confronted by a human. Venomous snakes should always be observed from a safe distance. Pit vipers are never safe to handle. Even dead ones can retain some neurological reflexes, and "road kills" have been known to bite. How to avoid and treat snakebites

Subspecies Mojave Desert (C. c. cerastes), bottom segment of rattle brown, 21 scale rows; extreme se. Utah, s. Nevada, and Mojave Desert region of California.
Sonoran (C. c. cercobombus), bottom segment of rattle black; 21 scale rows; sc. Arizona to w. central Sonora.
Colorado Desert (C. c. laterorepens), bottom segment of rattle black, 23 scale rows; sw. Arizona and se. California and adjacent Mexico.

Breeding Mates April to May, sometimes in fall. Female gives birth to 5-18 young, about 6 1/2-8" (17-20 cm) long, late summer to early fall.

Habitat Arid desert flatland with sandy washes or mesquite-crowned sand hammocks; below sea level to 5,000' (1,500 m).

Range S. Nevada and adjacent California, and extreme sw. Utah, south into Mexico.

Discussion Travels quickly over shifting surfaces by "sidewinding," a locomotion process in which the snake makes use of static friction to keep from slipping when crossing soft sandy areas. It leaves a trail of parallel J-shaped markings behind it. Primarily nocturnal, it is usually encountered crossing roads between sundown and midnight in spring. During the day it occupies mammal burrows or hides in shelters beneath bushes. Eats pocket mice, kangaroo rats, and lizards.