Pituophis catenifer
Pituophis catenifer is a species of nonvenomous colubrid snake endemic to North America. Nine subspecies are currently recognized, including the nominotypical subspecies, P. c. catenifer, described here. This snake is often mistaken for the prairie rattlesnake, but can be easily distinguished from a rattlesnake by the lack of a tail rattle, no black-and-white banding on its tail, and the shape of its head, which is narrower than a rattlesnake's. Additionally, rattlesnakes 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.
Etymology
The specific name, catenifer, is Latin for "chain-bearing", referring to the dorsal color pattern.
Description
Adult gopher snakes are typically between 36-84 in in length, when fully mature. Dorsally, gopher snakes are yellowish or a light, sandy brown, with a series of large, dark brown or black markings and smaller, darker spots along the sides. Ventrally, they are a lighter yellowish, either uniformly or with brown markings. They also come in several morphs, depending on the subspecies.
Behavior
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, but rather than delivering an open-mouthed strike, the gopher snake often strikes with a closed mouth, using its blunt nose to warn off possible predators. Additionally, gopher snakes vibrate their tails in a manner similar to rattlesnakes. One paper found that gopher snakes on islands lacking rattlesnakes vibrate their tails for shorter times than gopher snakes in mainland California, which is home to numerous rattlesnake species. This suggests that gopher snake-tail vibration may in fact be rattlesnake mimicry, since the behavior appears to be breaking down in areas without rattlesnakes, perhaps because predators on these islands have no reason to evolve to avoid tail-vibrating snakes.
Life expectancy
Wild gopher snakes typically live 12 to 15 years, but the oldest captive recorded lived over 33 years.
Common names for this species, or its several subspecies, are: Pacific gopher snake, Henry snake, coast gopher snake, bullsnake, Churchill's bullsnake, Oregon bullsnake, Pacific pine snake, western bullsnake, western gopher snake, Sonoran gopher snake, western pine snake, great basin gopher snake, blow snake, and yellow gopher snake.
Subspecies
As of 2022, nearly unanimous agreement exists on the recognition of six subspecies, occurring from southern Canada, the continental United States, and Mexico. However, no full agreement is found among taxonomists on the status of populations from Baja California and some offshore islands; the Cape gopher snake and central Baja Californian gopher snake are recognized, by some sources, as a single species. Some other sources, alternatively, consider it a species with two subspecies: P. v. vertebralis and P. v. bimaris. Other subspecies, including the Coronado Island gopher snake and San Martin Island gopher snake are of questionable validity.