The Western Plains Garter Snake

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Colubridae
Genus: Thamnophis
Species: Thamnophis radix
Subspecies: Thamnophis radix haydeni

Western Plains Garter Snake

Photo from the book
The Amphibians and Reptiles of Alberta
Russell and Bauer 1993


The western plains garter snake is a small slender snake between 500 and 1000 mm with some large females exceding 1000mm and is the largest of the three species of garter snakes in Alberta (the other two are the red-sided garter snake and the wandering garter snake). The body colour is greenish grey, light olive to brownish, with two rows of dark squarish spots forming a checkered pattern between the dorsal and lateral stripes. The dorsal stripe is orange-red to yellow, that fades posteriorly. The lateral stripes are normally yellowish or cream. The lips are light coloured, barred with black.

The fastest way of identification; if seen from above in the grass, (the way you are most likly to see a snake) is that if it appeares to be a dark or black snake with a red or orange stripe down the back, then it is the western plains garter snake.


The western plains garter snake can be found in grassy or brushy areas of southeast Alberta, mostly south of Cold Lake and east of Calgary. It can be active until mid-October on warm days, but will congregate at hibernacula when the weather cools. The hiberncula may be in the form of sink holes, mammal burrows or rock piles. This snake preys on small mammals worms and insects and will frequent ponds, streams, and marshes where it will take small fish and amphibians.

Mating may take place in the spring or fall and occures when the snakes gather at the hibernacula. Five to forty young are born alive from July onwards, and are about 180mm in total length.