DESCRIPTION: L=up to 4' (1.2m) or more. Overall tan brown with darker, diamond-shaped or hexagonal markings down the middle of the back. They have a light, diagonal stripe from behind their eyes to their upper lips forward of the corner of their mouth. They have black and white bands on their tail ("coon tail").
NATURAL HISTORY: Venomous. The toxin is extremely painful and medical attention should be sought immediately (the bite is potentially fatal -- when bitten, call the Arizona Poison and Drug Information Center at 626-6016 in Tucson or 1-800-222-1222 nationwide). See also section on Venomous Animals.

Carnivorous, feeding mostly on rodents, but also eating other small animals. Activity period depends on season; they are usually diurnal during spring and fall and nocturnal during summer, preferring temperatures between 70 and 90 degrees F (21-32 degrees C). Congregate in rocky cliffs (hibernaculum) during winter. In the spring, males will perform ritualized combat, where the two males raise their bodies up and push each other. The victor then has access to the females for mating. Sometimes, while the two males are "wrestling," a third male "sneaks" in and mates with the females (this often is referred to as the "sneaky male strategy" and is seen in other animals as well, for example the Creosote Bush Grasshopper). Gives birth to live young, that, by the way, are already venomous. See Rattlesnake Facts for more information.