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Canadian Herpetological Society Société d'Herpétologie du Canada |
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Bullsnake
Pituophis catenifer sayi
Family: Colubridae
The Bullsnake is a subspecies of the Gophersnake (Pituophis catenifer).
COSEWIC status:- Special Concern
- Special Concern
- Least Concern
Description
The Bullsnake is a large, heavy-bodied snake which may reach 2 m in total length. It is cream or yellowish with dark black, brown or reddish unconnected rectangular blotches down the back alternating with blotches on the sides to form a checkered pattern, and the tail has 9-19 dark bands. A dark line runs across the head in front of the eyes and two lines extend from each eye to the mouth: one straight down from the eye and the other toward the back of the mouth. The belly is cream coloured with brown markings, often forming a checkered pattern. The scales are keeled.
Similar Species
Bullsnakes may be confused with Prairie Rattlesnake and Western Hog-nosed Snakes. However, the rattlesnake has a distinctly triangular head, heat sensing pits on the face, a vertical pupil and usually a rattle at the tip of the tail. The Western Hog-nosed Snake has a characteristic upturned snout and more robust body.
Distribution
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This subspecies occurs in southwestern Saskatchewan, southeastern Alberta and south throughout the central United States and into northern Mexico. The seven sub-species of Gophersnake are widely distributed throughout North America and occur in British Columbia, Alberta, Saskatchewan and the western and central U.S. east to Indiana and south northern Mexico.
Habitat
This species inhabits open habitats such as grasslands and fields, sand hills, woodlands and scrubland. Bullsnakes hibernate, often communally with other snake species, in talus slopes and crevices in rocky habitat. This species lays its eggs on south facing slopes in mammal burrows or burrows excavated in loose sand and under rocks or logs. Mammal burrows, rocks, deadfall, shrubs and other cover are important microhabitats that are used for shelter and thermoregulation.
Biology
Bullsnakes mate in the spring and females lay an average of 11 eggs in mid-summer. The young hatch in August or early September and are 20-50 cm in length. Males of this species reach maturity in one to two years and females in three to five years, and individuals can live for more than 30 years. Bullsnakes primarily eat small mammals, especially rodents, and in doing so they provide excellent pest control around farms and human settlements. They also eat birds, birds' eggs, lizards and invertebrates. They are primarily active during the day but during very hot weather they may seek out underground retreat sites and become more active at night. Bullsnakes often travel large distances (> 1 km) between their hibernation site and summer habitat. When threatened, Bullsnakes may hiss loudly, vibrate their tail and rear up in a defensive posture.
Threats
Significant habitat loss, largely as a result of the conversion of prairie to agricultural uses, has occurred throughout this species’ Canadian range. Road mortality is also a threat to this species where roads bisect the species’ habitat. Like many snakes, Bullsnakes are often killed by misinformed people who either think they are dangerous or simply don't like snakes.