Eastern Garter Snake

Thamnophis sirtalis sirtalis
Wednesday, June 16, 2010

The garter snake, one of the most common snakes found around Mountain Lake, is characterized by a spotted or checkered black or brown body, with one distinct yellow or tan stripe running down its back, from its head to the tip of its tail, and two wider stripes on its sides. Its underbelly is the same yellow-tan color. Most adult snakes range from 18 to 26 inches; the record is over four feet. They are generally docile, and though they may be aggressive and strike an intruder, they are nonvenomous and their bites are not serious. They can be found all over the eastern US, extending into Canada, and inhabit a wide variety of environments: woodlands, meadows, marshes; they can even be found in some urban areas. They are able to swim, though rarely do.

They are peculiar among snakes in that garter snakes bear live young; anywhere from 10 to 30 young may be born ranging from 5 to 9 inches. The young are independent from birth. Most garter snakes hibernate in the wintertime, usually in groups, and are the first snakes to awaken in spring. They shed their skin occasionally, announcing it by turning their transparent eye-coverings to a milky blue, and abandon their old skin in exchange for a fresh one.

King snakes, predatory birds, and some small mammals are their natural predators, although humans and domestic cats are also major influences. Their diet consists mainly of earthworms, salamanders, slugs, insects, lizards, etc. (Although they can occasionally be found to eat an eastern red-spotted newt, despite the toxic chemical which newts contain, TTX; as is the subject of much research by Leleña. As a result of this, almost all garter snakes captured near the station will contain an internal pit tag as means of identification).

Although some garter snake subspecies are endangered, the eastern garter snake can be placed among the “lowest risk” category and is common across its range.

This specimen is a juvenile female captured by hand near the laundry room. Discrimination between the sexes is usually possible by examining the tail and anal area. Females have thinner, tapering tails whereas males’ tails are thicker until a point, where they taper rapidly. Further gender examination would necessitate a probe inserted into the snake’s vent.

Article by Hazel Galloway