Crotalus ruber

Common names: red diamond rattlesnake, red rattlesnake, red diamond snake,^[2] more.

Crotalus ruber is a venomous pitviper species found in the southwestern California in the United States and Baja California in Mexico. Three subspecies are currently recognized, including the nominate subspecies described here.^[3]

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Description

This is a moderately large species that commonly exceeds 100 cm on the mainland. Large males may exceed 140 cm, although specimens of over 150 cm are quite rare. The largest specimen on record measured 162 cm (Klauber, 1937).^[4]

Common names

Red diamond rattlesnake, red rattlesnake, red diamond snake, red diamond-backed rattlesnake, red rattler, western diamond rattlesnake.^[2] The form found on Cedros Island, previously described as C. exsul, was referred to as the Cedros Island diamond rattlesnake,^[5] or Cedros Island rattlesnake.^[6]

Geographic range

Found in the United States in southwestern California and southward through the Baja California peninsula, although not in the desert east of the Sierra de Juárez in northeastern Baja California. It also inhabits a number of islands in the Gulf of California, including Angel de la Guarda, Pond, San Lorenzo del Sur, San Marcos, Danzante, Monserrate and San José. Off the west coast of Baja California, it is found on Isla de Santa Margarita, which is off Baja California Sur, and (as C. exsul) on Isla de Cedros.^[1]

Originally, no type locality was given, although two have been proposed: "Dulzura, San Diego County, California", by Smith and Taylor (1950), and "vicinity of San Diego, California" by Schmidt (1953).^[1]

Conservation status

This species is classified as Least Concern (LC) on the IUCN Red List of Threatened Species (v3.1, 2001).^[7] Species are listed as such due to their wide distribution, presumed large population, or because it is unlikely to be declining fast enough to qualify for listing in a more threatened category. The population trend is down. Year assessed: 2007.^[8]

Habitat

Inhabits the cooler coastal zone, over the mountains and into the desert beyond. It prefers dense the chaparral country of the foothills, cactus patches and boulders covered with brush. Occurs from sea level to 1,500 m altitude.^[9]

Feeding

Feeds on rabbits, ground squirrels and birds.^[9] Wright and Wright (1957) also mention lizards and other snakes as being part of the diet of this species.^[2]

Reproduction

Mating occurs between February an April. Females give birth in August to between 3 and 20 young. Neonates are 30 to 34 cm in length.^[9]

Venom

Wright and Wright (1957) state that this species is of a mild disposition and has one of the least potent rattlesnake venoms, saying that they believe it does not come into snakebite statistics as do its relatives C. atrox and C. adamanteus.^[2]

Brown (1973) lists an average venom yield of 364 mg (dried) and LD₅₀ values of 4.0, 3.7 mg/kg IV, 6.0, 7.0, 6.7 mg/kg IP and 21.2 mg/kg SC for toxicity.^[10]

However, Norris (2004) warns that this species has a relatively large venom yield containing high levels of proteolytic enzymes, especially in the adults. A publication he mentions by Rael et al. (1986) showed that there are at least three proteolytic hemorrhagins that degrade fibrinogen and cause myonecrosis, but no Mojave toxin. On the other hand, three specimens from Mexico studied by Glen et al. (1983) did have Mojave toxin and lacked hemorrhagic activity.^[11]

Bite symptoms include massive tissue swelling, pain, ecchymosis, hemorrhagic blebs, and necrosis. Systemic symptoms may include nausea, vomiting, coagulopathy, clinical bleeding and hemolysis.^[11]

Subspecies

See also

• List of crotaline species and subspecies
• Crotalus by common name
• Crotalus by taxonomic synonyms
• Crotalinae by common name
• Crotalinae by taxonomic synonyms
• Snakebite

References