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Maritime Gartersnake

Thamnophis sirtalis pallidulus

Family: Colubridae

The Maritime Gartersnake is a subspecies of the Common Gartersnake (Thamnophis sirtalis).

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


The Maritime Gartersnake is highly variable in colour and pattern but tends to be brown, dark green or black with three yellow stripes: one down the back (dorsal stripe) and one on each side (lateral stripes). The lateral stripes are confined to the second and third scale row. Many individuals have white, brown or black chequered or speckled patterning along the back. The Maritime Gartersnake has a yellowish chin, upper jaw and belly. Individuals can grow to just under a metre in length.

Similar Species

Maritime Gartersnakes can be similar in appearance to Eastern Ribbonsnakes; however, the side stripes on the Eastern Ribbonsnake are on the third and fourth scale rows. Ribbonsnakes also have a distinct white crescent in front of the eye, have very clean-edged lateral stripes and are more slender than the garternakes. A young Maritime Gartersnake may be confused with a Red-bellied Snake. As the name suggests, Red-bellied Snakes have a red or orange belly and their lateral stripes are darker than the background colour.


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In Canada the Maritime Gartersnake occurs throughout Quebec, Nova Scotia, New Brunswick and Prince Edward Island. The various sub-species of Common Gartersnake occur throughout much of southern Canada and most of the United States, with the exception of the driest areas in the southwest.


The Maritime Gartersnake is a habitat generalist and can be found in a wide variety of habitats, including forests, wetlands, shrublands, shorelines, fields and rocky areas. This species also inhabits many urban and human-dominated landscapes. Maritime 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, rock crevices, crayfish burrows, anthropogenic structures (e.g. old foundations, cisterns), ant mounds and other underground cavities.


Maritime Gartersnakes breed in the spring, soon after emerging from hibernation. Females typically give birth to 6–40 live young in August. The young are 13–23 cm in length at birth and mature in two or three years. This species is the most commonly encountered snake in most parts of its range and adapts relatively well to human modification of the landscape. The Maritime Gartersnake eats a wide variety of food, including frogs, toads, salamanders, earthworms, small fish and mice. This species can live for more than twenty years.


Road mortality can be a significant threat to Maritime 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