Red rattlesnake, Red diamond snake, Red diamond-backed rattlesnake, Red rattler, Western diamond rattlesnake
The Red diamond rattlesnake (Crotalus ruber) is a venomous pit viper species found in the United States and in Mexico. These snakes are unique due to a common characteristic - a deep pit, or fossa, in the loreal area between the eye and the nostril on either side of the head. These loreal pits are the external openings to a pair of extremely sensitive infrared-detecting organs, which in effect give the snakes a sixth sense to help them find and perhaps even judge the size of the small, warm-blooded prey on which they prey.
The Red diamond rattlesnake 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.
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. They also inhabit 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, they are found on Isla de Santa Margarita, which is off Baja California Sur, and on Isla de Cedros. Red diamond rattlesnakes inhabit the cooler coastal zone, over the mountains, and into the desert beyond. They prefer the dense chaparral country of the foothills, cactus patches, and boulders covered with brush.
Red diamond rattlesnakes can be nocturnal or diurnal depending on the time of the year. They try to avoid heat and are usually active during cooler temperatures. These snakes lead a solitary lifestyle but hibernate in communal hibernacula. They are mainly terrestrial but may climb low vegetation and can swim.
This species is of a mild disposition and has one of the least potent rattlesnake venoms. Nonetheless, a bite from this snake is still a medical emergency and can be fatal without prompt antivenom treatment. Bite symptoms include massive tissue swelling, pain, ecchymosis, hemorrhagic blebs, and necrosis. Systemic symptoms may include nausea, vomiting, coagulopathy, clinical bleeding, and hemolysis.
Red diamond rattlesnakes are carnivores. They prey on rabbits, ground squirrels, birds, lizards, and other snakes. Snakes from coastal populations consume prey of larger body mass than snakes from desert populations.
Red diamond rattlesnakes are polygynandrous (promiscuous) meaning that both males and females have multiple partners during the breeding season. 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 and are independent at birth.
The main threat to this species is habitat loss due to residential and agricultural development.
According to IUCN Red List, the total population size of the Red diamond rattlesnake is unknown but probably exceeds 10,000 individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.
