The Great Basin Gopher Snake is large and robust with adults ranging from 76 -180 cm in British Columbia (St. John 2002). Body colour is tan with a row of dark brown or black blotches along the middle of the back and tail. The ventral surface is creamy yellow in colour. Distinctive markings on the head include a dark band on top of the head between the eyes and an angled dark stripe running from the eye to the back of the jaw. The body scales are keeled resulting in a rough texture. The pupils of the eye are round, there is a protruding rostral scale on the tip of the snout. The head is small and only slightly wider than the neck. In contrast, the Western Rattlesnake has a broad, triangle-shaped head, vertical pupils and a rattle at the end of the tail.
In British Columbia, Gopher Snakes emerge from hibernation in April and mating occurs throughout May (Waye and Shewchuk 2002). They are oviparous with a mean clutch size of 4.6 eggs laid in late June or early July (Shewchuk 1996). Nest sites often are communal, containing the eggs of several female Gopher Snakes, and may include the eggs of other species such as the Racer (Parker and Brown 1980; Shewchuk 1996). Hatchlings emerge in late August or early September after an incubation period of 60-80 days (Shewchuk 1996). At the northern limits of their range, females mature at a smaller body size and possibly at a later age and have smaller clutch sizes than populations farther south. In addition, most adult females likely reproduce every second year.
Gopher Snakes kill their prey by constriction or, in the case of smaller prey, by swallowing them alive. Their diet consists of ground squirrels, cottontail rabbits, pocket gophers, voles, deer mice, nestling birds and eggs, garter snakes, lizards and insects (Waye and Shewchuk 2002).
Gopher Snakes are most likely to be seen during the daytime in the spring and fall. During the heat of the summer, gopher snakes are most active at night, dawn and dusk and often spend daylight hours underground in vacant rodent burrows. They are good at burrowing, climbing and swimming. If threatened, a Gopher Snake may act aggressively and inflate its body, flatten its head, hiss loudly and shake its tail rapidly. However, they are non-venomous and pose no threat to humans.
In British Columbia, Gopher Snakes hibernate from November to March. They emerge from their dens in April and are known to migrate up to 2.2 km to egg-laying and summer foraging areas (Shewchuk 1996). In the summer, the majority of movements are less than 200 m between feeding and shelter areas. In mid-summer, they shed their skin and may be inactive for 10–15 days (Parker and Brown 1980; Shewchuk 1996).
In British Columbia, Gopher Snakes occur in open and semi-open habitats, primarily within the Bunchgrass and Ponderosa Pine biogeoclimatic zones. Valley bottoms and lower slopes below 700 m in elevation are preferred, but the species has been found up to 1676 m (Southern Interior Reptile and Amphibian Recovery Team 2008). Hibernacula (over-wintering sites) are usually located on south-facing slopes within fissures of rock outcrops or in talus and occasionally in rodent burrows. Gopher Snakes often hibernate communally with other snakes such as Rattlesnakes, Racers and Garter Snakes and use the same hibernacula each year (Bertram 2004). Egg-laying sites are often located on open south-facing slopes with loose sandy soils where the female makes a shallow burrow or modifies existing rodent burrows. Egg-laying sites also have been found on talus slopes, rock fissures, and under decaying wood (Waye and Shewchuk 2002). Gopher snakes forage in grasslands, meadows, marshes and riparian areas where they feed primarily on small mammals. They use retreat sites such as abandoned rodent burrows and rock piles in close proximity to foraging areas for shelter and thermal protection (Shewchuk 1996).
The Great Basin Gopher Snake is widely distributed in the western United States including eastern Washington and Oregon, southeastern California, and parts of Idaho, Utah, Wyoming, Colorado, Arizona, and New Mexico. The species reaches its northernmost distribution in south-central British Columbia, where it has a patchy distribution. It occurs within the arid interior of the province including the Okanagan, Similkameen, Kettle, Granby, Nicola, Thompson, and Fraser watersheds (Gregory and Campbell 1984, Southern Interior Reptile and Amphibian Recovery Team 2008). Highest densities are found at low elevations within the Okanagan and Thompson valleys (Bertram 2004).
Habitat loss and degradation due to residential, industrial and agricultural development is the main threat to Gopher Snake populations in British Columbia (Southern Interior Reptile and Amphibian Recovery Team 2008). Winter den sites are vulnerable to destruction and travel routes to them may be cut-off. The availability of foraging areas, summer burrows and egg-laying sites are reduced by ploughing and other land conversions. Pesticide use reduces rodent populations, especially pocket gophers, resulting in reduced prey and availability of underground burrows used for shelter and egg-laying. Gopher snakes are often mistaken for the similar rattlesnake and killed unnecessarily. They are also frequently killed by traffic when crossing roads. Gopher snakes are at the northern limits of their range and due to a harsh climate and reduced reproductive capacity, they are limited in their ability to recover from population declines.
The Great Basin Gopher Snake (Pituophis catenifer deserticola) is the only extant sub-species in British Columbia. A second subspecies, the Pacific Gopher Snake (Pituophis catenifer catenifer), once occurred in southwestern BC but is now considered extirpated. A third subspecies in Canada, the Bullsnake (Pituophis catenifer sayi), occurs in southern Alberta and Saskatchewan.
Gopher Snakes are non-venomous and harmless to humans. They are predators of small mammals including rodent pests that cause agricultural losses.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC:
Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab
for Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2022-05-16 8:07:42 AM]
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