Bullsnake / Gopher Snake

Pituophis catenifer


Bullsnakes are the largest snake species in Alberta, reaching up to 2 m in length. They are heavy-bodied, light colored, with dark brown, black or reddish rectangular blotches along their length. Bullsnakes are also the only snake species in Alberta that kills their prey by constriction. As recent research has shown, constrictors do not actually kill their prey by suffocating them, as previously believed. Instead, they squeeze their prey, causing severe derangement in their blood pressure, causing circulatory collapse. Bullsnakes are primarily rodent-eaters, but will also eat birds and eggs. Because of their taste for rodents, they are valuable as a natural biological control for farmers. Bullsnakes are oviparous, meaning that they lay eggs. They can lay 2-24 eggs, 1-2 times during the summer. Young snakes emerge in the late summer or early fall.


Bullsnakes are burrowers, using their modified rostral (nose) scale to dig. They are diurnal (most active during the day). They are found in desert, short-grass prairie, and dry, open scrubland habitats in the south eastern corner of Alberta, with the Red Deer River basin being the northern edge of their range. When herping, look for rock piles and boulders in areas with sandy soil.


Threats to the Bullsnake include cultivation and irrigation of their grassland habitats, increased road density (road mortalities). Sadly, they are also the victims of human persecution, primarily directed at their hibernacula (the gathering place where they hibernate), as the snakes are big, look a bit like rattlesnakes, and will shake their tails when frightened (though they do not have rattles). There is insufficient population information for us to determine their threat status at this time.

Alberta Conservancy Association “Reptiles of Alberta”
External link opens in new tab or window Canadian Herpetological Society
External link opens in new tab or window COSEWIC Species Database: Bullsnake.

Photo by Kyle Welsh