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Plains Gartersnake

Thamnophis radix

Family: Colubridae

COSEWIC status:
  • Not Assessed
SARA status:
  • No Status
IUCN status:
  • Least Concern


The Plains Gartersnake is tan to black with a bright yellowish-orange dorsal stripe running down the back and a lighter yellow lateral (side) stripe on each side that runs along the third and fourth scale rows. This species has black bars on the upper lip. Individuals can grow to over a metre in length.

Similar Species

The Plains Gartersnake may be confused with the Terrestrial Gartersnake and the Red-sided Gartersnake. In the case of both of these species, the side stripe is on the second and third scale row, the dorsal stripe is not as vibrant and they lack the black bars on the upper lip. Further, the rows of black spots on the Terrestrial Gartersnake invade the dorsal stripe, causing the dorsal stripe to have a jagged or wavy edge and the Red-sided Gartersnake has distinct red bars on the sides of its body between the dorsal and side stripes.


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In Canada the Plains Gartersnake is found in the southern parts of Manitoba, Saskatchewan and Alberta. In the United States it is distributed through the Great Plains as far south as New Mexico.


The Plains Gartersnake inhabits grasslands, meadows and open woodlands and is often found near wetlands lakes and streams. Plains Gartersnakes 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 (e.g. ground squirrels), rock crevices, crayfish burrows, anthropogenic structures (e.g. old foundations, cisterns), ant mounds and other underground cavities.


Like other gartersnakes, the Plains Gartersnake is live-bearing rather than egg-laying. Five to 40 young are born in mid to late summer and they may be up to 19 cm in length. The Plains Gartersnake feeds on fish, amphibians, small mammals, worms and insects. It commonly hunts along the edge of water and may swim to escape predators. This species can live for more than 10 years.


Road mortality can be a significant threat to Plains 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. 

Additional Information About This Species In Canada