|
Canadian Herpetological Society Société d'Herpétologie du Canada |
|---|
Terrestrial Gartersnake
Thamnophis elegans
Family: Colubridae
The subspecies of Terrestrial Gartersnake that occurs in Canada is the Wandering Gartersnake (Thamnophis elegans vagrans).
COSEWIC status:- Not Assessed
- No Status
- Least Concern
Description
The Terrestrial Gartersnake can reach just over a metre in total length. It has a distinct pale yellow stripe down the back (dorsal stripe) as well as along each side (lateral stripes). The lateral stripes are on the second and third scale rows. The background colour is brown, grey or green with two rows of darker spots between the stripes. The darker spots often invade the stripe along the back and make it look jagged or wavy. Unlike the other species of Gartersnake that overlap with its range, the Terrestrial Gartersnake usually has eight scales on its upper lip, two of which are enlarged. This species can grow to just over a metre in length, but most individuals are less than 80 cm in length.
Similar Species
The Terrestrial Gartersnake may be confused with several other species of gartersnake with which its range overlaps in Canada: Common Gartersnake, Plains Gartersnake and Northwestern Gartersnake. The Common and Northwestern Gartersnakes typically have only seven scales on the upper lip. The western sub-species of the Common Gartersnake often have red bars on the sides between the dorsal and lateral stripes. The Plains Gartersnake has distinct black bars on the scales of the upper lip, its lateral stripes are on the on the third and fourth scale rows and the dorsal stripe is often a vibrant yellow or orange.
Distribution
Click for larger image
The Terrestrial Gartersnake is widely distributed in southern British Columbia, Alberta and southwestern Saskatchewan. The North American range of this species extends through the United States south to New Mexico.
Habitat
The Terrestrial Gartersnake is a habitat generalist and can be found in a wide variety of habitats, including lowlands, rocky hillsides, grassland, woodland, forest clearings and wetlands as well as near streams, rivers and ponds. This species typically occurs in areas with vegetation. Individuals are commonly found under cover objects, such as rocks and logs, which provide important microhabitat for shelter and thermoregulation. They overwinter – often communally – below the frost line in mammal burrows, rock crevices, talus slopes and anthropogenic structures (e.g. old foundations, cisterns).
Biology
Like other Gartersnakes this species bears live young rather than eggs. From 4–19 young may be born in a litter in mid to late summer. The Terrestrial Gartersnake eats a variety of invertebrate and vertebrate prey captured both in the water and on land. Large numbers may hibernate together in mammal burrows or natural crevices and be found together on emergence in the spring. This species can live for more than twenty years.
Threats
Road mortality can be a significant threat to Terrestrial Gartersnake populations located near busy roads. Although intensive habitat loss is a threat to all snakes, this species is able to persist in areas with low to moderate human disturbance. Human persecution and subsidized predation may also present a risk to this species in areas of high human density.