Rattlesnake, Southern Pacific

The southern Pacific rattlesnake is one of the nine subspecies of western rattlesnakes, which range across much of the western United States, Mexico and Canada. Like its relatives, the southern Pacific rattlesnake has a relatively hefty body and stubby tail, a triangular-shaped head, hooded eyes and elliptical pupils. Like not only rattlesnakes but also like the cottonmouth water moccasins and the copperheads, the southern Pacific rattler has a small opening, or heat-sensing organ called a loreal pit, on each side of its face, between its nostrils and eyes, giving it membership in the subfamily called "pit vipers."