Geographic range: Nearctic, Neotropical: USA and Mexico. From southwestern Texas, New Mexico and southern Arizona, southward through Coahuila, and western Nuevo Leon, Chihuahua and northeastern Sonora, southwestern Tamaulipas, western San Luis Potosi, Aguascalientes, northern Jalisco, Zacatecas and southern Sinaloa.

Physical characteristics: Small ( maximum length 83 cm) gray, pink or tan rattlesnake, with a pattern of 13-24, narrow, dark brown or black irregularly spaced bands bordered by paler segments. Small spots may occur between the bands. The belly normally is pink with suffused spots.

Food habits: Seems to prefer reptiles over mammals and amphibians. Rock rattlesnake taken in the wild are known to have eaten lizards of the genera Sceloporus, Urosaurus, Phrynosoma, Hoolbrookia and Aspidocelis.

Reproduction: This species is viviparous and little is known about reproduction. Sexual maturity in females is probably attained at a total length of about 40 cm, comparable maturity data are lacking for male as are also data on both sexual cycles. Courtship and mating have been observed in September and October in captivity, the young are normally born during late july and august, litters ranges from one to eight young.

Behavior: The annual activity period is throughout the year, especially in spring and fall, if the temperature is warm, most activity is diurnal.

Habitat: The rock rattlesnake inhabits arid to semiarid areas at medium elevation 600 m to 2285, It is most often associated with rocky areas, slopes, outcroppings with crevices and pines forest.


text: © Alfonso Delgadillo