| Crotalus ruber | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Subphylum: | Vertebrata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Family: | Viperidae |
| Subfamily: | Crotalinae |
| Genus: | Crotalus |
| Species: | C. ruber |
| Binomial name | |
| Crotalus ruber Cope, 1892 |
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| Synonyms | |
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Crotalus ruber is a venomous pitviper species found in 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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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]
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]
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]
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]
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]
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]
Mating occurs between February and April. Females give birth in August, to between 3 and 20 young. Neonates are 30 to 34 cm in length.[9]
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[3] | Taxon author[3] | Common name | Geographic range[1] |
|---|---|---|---|
| C. r. exsul[4] | Garman, 1884[4] | Cedros Island diamond rattlesnake | Mexico, Cedros Island.[5] |
| C. r. lorenzoensis | Radcliff & Maslin, 1975 | San Lorenzo Island rattlesnake | Mexico, San Lorenzo Island in the Gulf of California. |
| C. r. lucasensis | Van Denburgh, 1920 | San Lucan diamond rattlesnake | Mexico, cape region of lower Baja California. |
| C. r. ruber | Cope, 1892 | Red diamond rattlesnake | The United States in southwestern California and Mexico in Baja California, except for the cape region of lower Baja California. |
A study by Murphy et al. (1995) concluded that there was not enough genetic and morphological diversity between C. exsul from Cedros Island and C. ruber from the mainland to warrant the recognition of both species. Since C. exsul Garman (1884) has priority over C. ruber Cope (1892), they suggested that the island population be referred to as C. e. exsul and those from the mainland as C. e. ruber. In response to this, Smith et al. (1998) petitioned the ICZN to validate ruber over exsul in the interest of nomenclatural stability. In 2000, the ICZN published Opinion 1960 in which they ruled that C. ruber should have precedence over C. exsul.[4]