Red diamond rattlesnake

Crotalus ruber is a venomous pit viper 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. This moderately large species commonly exceeds 100 cm (39 in) on the mainland. Large males may exceed 140 cm (55 in), although specimens of over 150 cm (59 in) are quite rare. The largest specimen on record measured 162 cm (64 in) (Klauber, 1937). Crotalus ruber is very similar in pattern to C. atrox, but it is distinguished by its reddish color, to which the specific name, ruber, refers. Also, the first lower labial scale on each side is transversely divided to form a pair of anterior chin shields. The dorsal scales are usually arranged in 29 rows, but may vary from 25 to 31 rows. Ventrals range from 185 to 206. Snakes found in coastal regions are longer on average than those found in desert regions. Common names include: red diamond rattlesnake, red rattlesnake, red diamond snake, red diamond-backed rattlesnake, red rattler, and western diamond rattlesnake. The form found on Cedros Island, previously described as C. exsul, was referred to as the Cedros Island diamond rattlesnake, or Cedros Island rattlesnake. Red diamond rattlesnakes are 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. 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).