Garter Snake

Garter Snake — A garter snake is any species of North American snake within the genus Thamnophis. Because of the similarity in sound of the words, combined with where people often see them, they are sometimes called garden snakes or gardner snakes. They are not venomous.

Garter snakes are common across North America, from Canada to Central America. They are the single most widely distributed species of reptile in North America, and is a common sight in American gardens, giving rise to its “garden snake” nickname. In fact, the common garter snake, T. sirtalis, is the only species of snake to be found in Alaska, and is one of the northernmost species of snake in the world, possibly second only to the Crossed Viper, Vipera berus. The genus is so far ranging due to its unparticular diet and adaptability to different biomes and landforms, from marshes to hillsides to drainage ditches and even vacant lots, in both dry and wet regions, with varying proximity to water and rivers. However, in the western part of North America, these snakes are more water-loving than in the eastern portion. Northern populations hibernate in larger groups than southern ones. Despite the decline in their population from collection as pets (especially in the more northerly regions in which large groups are collected at hibernation), pollution of aquatic areas, and introduction of bullfrogs and bass as predators, this is still a very commonly found snake. The San Francisco garter snake, Thamnophis sirtalis tetrataenia, however, is an endangered subspecies and has been on the endangered list since 1967. Predation by crayfish has also been responsible for the decline of the narrowhead garter snake, T. rufipunctatus.

There is no real consensus exactly how many species of Thamnophis there are, and disagreement among taxonomists and sources, such as field guides, over whether two types of snakes are separate species or subspecies of the same species is common. They are also closely related to the snakes of the genus Nerodia, and some species have been moved back and forth between genera.

Garter snakes, like all snakes, are carnivorous. Their diet consists of almost any creature that they are capable of overpowering: slugs, earthworms, insects, leeches, lizards, amphibians, birds, fish, and rodents. When living near the water, they will eat other aquatic animals. The ribbon snake in particular favors frogs (including tadpoles), readily eating them despite their strong chemical defenses. Food is swallowed whole. Although they dine mostly upon live animals, they will sometimes eat eggs.