This species has one of the widest ranges of any North American snake. At one extreme, the common garter snake lives on the southern shores of Hudson Bay in eastern Canada and survives the long and icy sub-Arctic winters. At the other end of its range, it lives in the humid, subtropical swamps of Florida. The coloration is, therefore, extremely variable, but the garter snake nearly always has distinctive back and side stripes. It is active during the day and hunts for frogs, toads, salamanders and small invertebrates among damp vegetation on the ground. One of the few snakes to occur in the far north, the garter snake is able to withstand cold weather well and is found as far as 67 degrees North. In the southern part of its range, it may remain active all year round, but in the north it hibernates in communal dens.
Garter snakes are closely associated with water. They are able swimmers, but search for prey both in and out of water. Garter snakes are active hunters and generally have to pursue their victims. They seek out meals by poking their small heads into nooks and crannies and flushing out prey. The snakes' long bodies allow them to move with great speed, and their large eyes are well suited to tracking fleeing prey.
Garter snakes have long bodies and small heads. They are found in a variety of colours, which provide camouflage in different habitats.
Garter snakes hibernate in burrows, and many snakes may crowd into a suitable hole. Mating takes place soon after hibernation. In northern regions with short summers, the pressure to mate quickly is very strong, while in the south of the range the snakes have a longer breeding season. They may, however, mate in autumn, in which event the sperm spend most of the winter in the female's oviduct and do not move into position to fertilize the eggs until spring. Before copulation, the male snake throws his body into a series of waves and then rubs his chin over the female's body. The tubercles on his chin must receive the right sensory responses before he will mate. As many as 80 young develop inside the female's body, nourished by a form of placenta, and are born fully formed.
Distribution: Southern Canada to Florida.
Habitat: Close to water.
Food: Worms, fish and amphibians.
Size: 65 - 130 cm (25 - 51 in).
Maturity: Not known.
Breeding: Mate after hibernation.
Life span: Unknown.