Kingdom Animalia Subphylum Vertebrata Suborder Serpentes Scientific name Crotalus oreganus helleri Rank Subspecies | Phylum Chordata Order Squamata Family Viperidae Higher classification Crotalus oreganus | |
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Similar Crotalus oreganus, Snake, Rattlesnake, Crotalus ruber, Crotalus viridis | ||
Crotalus oreganus helleri
Crotalus oreganus helleri is a venomous pit viper subspecies found in southwestern California and south into Baja California, Mexico.
Contents
- Crotalus oreganus helleri
- Crotalus oreganus helleri southern pacific rattlesnake
- Etymology
- Description
- Common names
- Venom
- Geographic range
- References
Crotalus oreganus helleri southern pacific rattlesnake
Etymology
The specific name, helleri, is in honor of American zoologist Edmund Heller.
Description
Adults are 24-55 inches (61–139 cm) in length.
The color pattern consists of a pale brown, gray-brown, or yellowish brown ground color overlaid with a series of large, dark brown dorsal blotches that may or may not have pale centers. The blotches are more diamond shaped, as opposed to those of C. o. oreganus that are more hexagonal, and are bordered by light scales. The tail rings are not clearly defined. In juveniles, the end of the tail is bright orange, but this turns to brown as the snakes mature. In adults, the base of the tail and the first segment of the rattle are brown. The postocular stripe is moderately to very clearly defined. In juveniles, this stripe is bordered above by a pale stripe, but as the snakes mature this turns to drab yellow or brown. A conspicuous pale crossbar is sometimes present across the supraoculars, after which the head is a uniform dark color. In some older snakes the head is mostly dark with almost no trace of the supraorbital crossbar, or none at all.
Common names
Common names include Southern Pacific rattlesnake, black diamond rattlesnake, black (diamond) rattler, gray diamond-back, mountain rattler, Pacific rattler, and San Diegan rattler.
Venom
Crotalus oreganus helleri has a highly toxic venom that is much like mojave toxin in the way it attacks nerve endings. It also contains myotoxins and hemotoxins and can easily give a fatal bite. The venom from this snake also requires a much higher dose of Crotalidae polyvalent immune fab ("Crofab"), an antivenom used to treat the bite of North American pit vipers.
Geographic range
This snake is found in the United States in southern California, and in Mexico in northern Baja California, west of the desert. In the north it is found from the counties of San Luis Obispo and Kern, and south through the counties of Santa Barbara, Ventura, Los Angeles (including Santa Catalina Island and the foothills.), southwestern San Bernardino, Orange, western Riverside, San Diego and extreme western Imperial. From there its range extends south through Baja California to lat. 28° 30' North. According to Klauber (1956), the type locality is "San Jose, Lower California" [San José, lat. 31° N, Baja California (state), Mexico].