Canada, often associated with vast, cold landscapes, hosts a diverse array of snake species. These reptiles thrive across various Canadian environments, highlighting their adaptability to different climates. Their presence reveals a fascinating aspect of Canada’s biodiversity.
Diverse Species Across the Landscape
Canada is home to approximately 26 different snake species, with a majority being non-venomous and playing important roles in their ecosystems. Among the most widespread are various garter snakes, such as the Common Garter Snake and the Western Terrestrial Garter Snake, found in almost every province and territory except Yukon, Nunavut, and Newfoundland and Labrador. These adaptable snakes measure between 40 to 80 centimeters and are identifiable by their striped patterns, often yellow, green, or white. They are frequently encountered in gardens and parks.
The Northern Watersnake, another common non-venomous species, is found basking on rocks or logs near slow-moving water bodies like ponds and rivers. This snake has dark bands on a lighter background and is an excellent swimmer, primarily preying on fish and amphibians. The Milk Snake, often mistaken for venomous species, is a harmless constrictor found in forests, fields, and rocky areas. Its reddish-brown blotches outlined in black on a gray or tan background make it distinctive. Other non-venomous species include the Smooth Green Snake, known for its camouflage in grassy areas, and the Gray Ratsnake, which can reach lengths of up to 2 meters, making it Canada’s longest snake.
Identifying Venomous Versus Harmless
Of Canada’s approximately 26 native snake species, only four are venomous. One, the Timber Rattlesnake, is now extirpated from Canada. The primary venomous snakes found are the Massasauga Rattlesnake, the Western Rattlesnake, and the Prairie Rattlesnake.
Distinguishing these venomous snakes from their harmless counterparts is possible through specific visual cues. Venomous snakes possess a triangular or diamond-shaped head, distinct from the more rounded heads of non-venomous species. Their pupils are vertical slits, resembling a cat’s eye, whereas non-venomous snakes have round pupils. Rattlesnakes have a rattle at the end of their tail, which they vibrate as a warning.
The Massasauga Rattlesnake, Ontario’s only venomous snake, measures 45-75 centimeters, with a grey or tan body and dark blotches. The Western Rattlesnake, found in British Columbia, measures 60 to 150 centimeters long and features dark-brown blotches on a brown to yellowish body. The Prairie Rattlesnake inhabits Alberta and Saskatchewan.
Geographic Distribution and Habitats
Snakes in Canada are primarily concentrated in the southern regions of the country, where milder climates allow them to thrive. These reptiles are ectothermic, meaning they rely on external heat sources to regulate their body temperature, which limits their northern range. Most Canadian snakes reside below the 60th parallel, with the common garter snake extending further north into the Northwest Territories.
Southern Ontario, particularly around the Great Lakes, is a key area for snake populations, including the Massasauga Rattlesnake. British Columbia, especially its southern interior valleys like the Okanagan Valley, supports populations of the Western Rattlesnake and various garter snakes. The Prairie Rattlesnake is found in the grasslands and semi-desert shrublands of southern Saskatchewan and Alberta.
Snakes inhabit various natural environments, including forest clearings, edges, fields, wetlands, and rocky outcrops. Some species, like the Northern Watersnake, prefer aquatic habitats such as ponds and slow-moving rivers, while others, like the Milk Snake, can be found in agricultural fields and even around human dwellings. During the cold Canadian winters, snakes hibernate underground in places like rock crevices, mammal burrows, or ant mounds to escape freezing temperatures.