The Baja California Rattlesnake is a medium sized rattlesnake growing to 20-31 inches in length (50-80 cm). This species has a relatively small head with a eye stripe extending from the back of the eye. Its coloration varies from tan to dark brown, grayish brown to silvery gray, and may gradually lighten posteriorly. The individuals in the southern portion of its range tend to be lighter then those in the more northern areas. The underside of the snake is cream colored with gray to brown dotting.
The maximum reported length of this species is 89.8 cm. It is sexually dimorphic, with the males typically being larger than the females. The head is remarkebly small and narrow, while the eyes are proportionately large.
Found in western Mexico. In the north it is found in the Baja California Peninsula from around Río San Telmo on the west coast and from opposite Isla Angel de la Guarda on the gulf coast, south to Cabo San Lucas. Also found on the following islands in the Gulf of California: San Marcos, Carmen, San José, San Francisco, Partida del Sur, Espírita Santo and Cerralvo. Off the pacific coast it is also found on the island of San Margarita. The type locality is "Cape San Lucas, Baja California Sur.
Prefers desert, but in the northwestern part of its range it can be found in chaparral country, while in the cape region (Sierra de San Lázaro) it occurs in pine-oak and tropical deciduous forest. It can be found in rocky areas with arid thronscrub and cacti, but sometimes also in sand dunes. Often attracted to human habitation where it has been found in piles of refuse
Captive specimens have produced litters of 2-7 young. New born specimens with lengths of between 20.6 and 22.2 cm have been mentioned. Reports of finding neonates in the wild between late July and mid October, which would indicate that the species mates in the spring and gives birth in the summer or early fall.
The venom contains at least two poisonous substances, both protein in nature. One is a powerful depressant of heart and lung action; the other is a tissue-disintegrating agent.
Snakes of this species, regardless of their size, are known to eat small rodents, lizards, and centipedes. This is in contrast to many other rattlesnake species that prey on lizards almost exclusively as juveniles, switching to mammals as adults. With C. enyo, small snakes eat lizards more often than do large ones, and large snakes eat mammals more often than do small ones. Adults also prey on large centipedes of the genus Scolopendra.