Description: Adults are 17 to 33 inches long. (43 - 84 cm). Snakes encountered will generally be 12 to 18 inches long. Juveniles are about 7 inches long at birth. A heavy-bodied venomous pit viper with a thin neck, a large triangular head, and a thick tail with a rattle on the end made of loose interlocking segments. A new rattle segment is added each time the skin is shed, which can be more than one time per year. Pupils are elliptical. Scales are keeled. The supraocular scale over each eye is enlarged and raised up over the eye giving the appearance of a "horn" over each eye. These scales can fold down over the eyes to protect them when the snakes is buried or crawling in underground burrows. Has two pits, one on each side of the front of the head above the mouth that are used to sense heat when hunting warm-blooded prey. The dark segment of the rattle closest to the body on an adult C. c. cerastes is brown. Color and Pattern: Pale cream, tan, brown, pink, or grayish back color usually closely matches the soil surface allowing the snake to blend in with the background. Around 40 darker blotches on the back. A dark stripe extends through each eye. Young: Juveniles are born with only a single rattle button at the end of the tail.

Habitat: Inhabits primarily areas of wind-blown sands, especially where sand hummocks are topped with vegetation. Also found in hardpan, open flats, rocky hillsides, and other desert areas, especially those grown with creosote bush, where the terrain is open, not obstructed by rocks or vegetation, allowing the broad sidewinding locomotion.

Range: This subspecies, Crotalus cerastes cerastes - Mohave Desert Sidewinder, is found in south-central California south and east of the Sierras south to roughly the San Bernardino county line.

Found in these States: AZ | CA | NV | UT

Venom: These snakes are venomous, but possess a weaker venom than many other rattlesnakes. This, together with the smaller size of their venom glands, makes them less dangerous than their larger relatives. Regardless, any rattlesnake bite can be fatal and should be taken seriously and medical attention sought immediately.

Envenomation can cause pain, swelling, hemorrhagic bleb formation, and ecchymosis (i.e., bruising). Swelling, while not particularly severe, occasionally may involve entire limbs and the trunk. Envenomation's systemic symptoms include nausea, dizziness, chills, coagulopathy (blood disorders), and shock. There is an account of a man who had been bitten on the first joint of the index finger of the right hand, with only a single fang penetrating. Although the bite was described as no more painful than a pin prick, a doctor was seen within about 25 minutes, and 10 cm3 of antivenin were administered. Within 2.5 hours, his entire arm was swollen and the pain was severe, "as if the arm were soaked in a bucket of boiling oil."

Ovine-derived antivenom, CroFab, for North American pit viper envenomation, has been widely available since 2001. Consultation with a local expert or regional poison control center should be obtained before administering antivenom. The previous antivenin (ACP) is no longer manufactured.

Diet: Eats mainly lizards when young, and increasingly larger prey including small rodents when grown. An ambush hunter, it sits buried beneath the surface of loose sand with just the top of the head showing, near kangaroo rat warrens, and lizard or rodent trails, then strikes at and releases the prey. The snake then follows the trail of the envenomated animal and swallows it whole.

Reproduction: Rattlesnakes are ovoviviparous. The mother keeps her fertilized eggs inside her body and gives birth to living young. Females probably start bearing young at three years of age and breed annually. Mating occurs in the spring. Two to 18 young are born from July to September.

Status: Listed as Least Concern in view of its wide distribution, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.

Arizona list C.c. cerastes as vulnerbale and Utah list it as Imperiled. California and Nevada have it listed as Secure.

Taxonomy: