SPECIES NAMECrotalus1 scutulatus2
SUBSPECIESNorthern Mojave Rattlesnake Crotalus scutulatus scutulatus
FAMILYViperidae (vipers), Subfamily Crotalinae (pit vipers)
CALIFORNIA RANGESoutheastern California
RISK TO HUMANSDangerous/Highly venomous
VENOM CATEGORYHemotoxic, Neurotoxic
1. Crotalus, Greek krótalοn meaning “rattle” or “castanet” referring to the rattle on the end of the tail.
2. Scutulatus, Latin, scutulātus = diamond or lozenge-shaped, referring to the dorsal pattern.
A medium-sized pit viper with keeled scales, elliptical eyes, spade-shaped head, infrared pits on either side of the head between their eye and nostril, and a distinctive rattle at the tip of its tail. The unique color variation of this species ranges from brown, tan, and yellow to pale green and olive green hues which earned them the nickname “Mojave greens.” Patterns consist of dark well-defined diamond or near diamond shaped blotches along the dorsal surface with similar smaller blotches along the sides. The tail has distinct contrasting black and white bands with black bands narrower than white bands. Two distinct white stripes extend from the front and rear of the eye diagonally back toward the upper lip. Adult range from 24-51 inches in length, more commonly reach 18-40 inches. Males are generally larger than females.
Range is limited to southeastern California from the Colorado River, west through the Mojave Desert to the Antelope valley. Typically inhabits xeric environments consisting of grasslands, desert scrub, rocky slopes, creosote bush flats, open juniper woodland, Joshua tree forests, cacti, and light chaparral. Often associated with creosote, mesquite, sage, and cacti. Range overlaps with that of the western diamond-backed rattlesnake which prefers dense cover. This species prefers areas with sparse shrub cover.
Specializes in small mammals such as ground squirrels, mice, kangaroo rats, and immature rabbits and hares. Secondary prey occasionally include lizards, toads, and other snakes. Juveniles likely show an ontogenetic preference for lizards while transitioning to mammals as adults.
Active from April through September depending on environmental conditions. Typically unaggressive but can be easily provoked and very defensive. It may raise its head and upper body in a coiled manner mimicking the aggressive posture of the western diamond-backed rattlesnake. Primarily nocturnal and crepuscular during warmer months, but may be active throughout the day during cooler periods. Will seek cover under creosote or other shrubs and in burrows to escape heat. Species may also climb into branches of shrubs, but uncommon.
Mating occurs in the spring after emergence from overwintering retreats from late March to early May and in late summer from mid-July to early September. Females give birth to 2-17 live young between July and September. Neonates measure approximately 10.5 inches at birth and are born with a single button at the end of the tail that doesn’t produce the rattle sound until additional segments are added during successive shedding. An ovoviviparous species requires considerable energy from the female, fertilized eggs are retained and prior to birth the young pierce the egg membranes and are born live.
Venom consist hemorrhagic (Type B) and a presynaptic neurotoxin, a combination of two peptide subunits, each on their own less lethal then the combination, creating a highly potent neurotoxin called the Mojave toxin (Type A). A subpopulation of Mojave rattlesnakes in Arizona lack the Type A neurotoxin but it is found in all subspecies inhabiting California. Hemorrhagic effects cause persistent bleeding while neurotoxins cause skeletal weakness, respiratory paralysis, cardiovascular, and circulatory failure. Often considered to be the most venomous rattlesnake in the U.S. The bite from one Mojave rattlesnake has enough venom to kill 10 people. An antivenin with a high titer against Mojave toxin is indicated upon envenomation.
Inyo*, Kern, Los Angeles, and San Bernardino counties.
*Indicates counties where the species’ range extends only into a minor portion of the county.