Additionally, rattlesnakes (and indeed most vipers) possess a large venom gland located behind each eye, giving their heads a much rounder, more angular shape, as opposed to the more cylindrical, slender head shape of a gopher snake or other colubrid.

The specific name, catenifer, is Latin for "chain-bearing", referring to the dorsal color pattern.

[citation needed] The gopher snake has a unique defensive mechanism, in which it puffs up its body and curls itself into the classic strike pose of a rattlesnake.

[5] As of 2022, there is nearly-unanimous agreement on the recognition of six subspecies, occurring from southern Canada, the continental United States, and Mexico.

However, there is not full agreement among taxonomists on the status of populations from Baja California and some offshore islands; the Cape gophersnake (Pituophis catenifer vertebralis) and central Baja Californian gophersnake (P. catenifer bimaris) are recognized, by some sources, as a single species (with no subspecies vertebralis).