University of Massachusetts Amherst

Massachusetts North American Amphibian Program

Eastern Gartersnake

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Herp Atlas 1992-1998 Survey

  • The map below shows the distribution of the Common Garter Snake in Massachusetts based on the original intensive volunteer survey that took place from 1992-1998.
  • Download pdf of map

Updated Distribution Map

Thamnophis s. sirtalis (18-26", up to 48")

Common Garter Snake
Common Garter Snake
Common Garter Snake

Generally, you can recognize this most common of all New England snakes by its pattern of yellow stripes on a black or brown background. Although the pattern is variable, it usually consists of a narrow stripe down the middle of the back and a broad stripe on each side. Between the center and each side stripe are two rows of alternating black spots. A dark line separating the yellow side stripe from the belly is not particularly bold as it is in the ribbon snake. Background color is usually brown or black, but may be somewhat green or reddish. Stripes may be tan, yellow or orange. A garter snake will occasionally appear more checkered than striped. The scales are keeled and the belly is yellow or pale green.

Garter snakes generally mate after emerging from hibernation in March or April. Females give birth to 12-40 young any time from July through October.

Garter snakes occupy a variety of habitats including pond and stream edges, wetlands, forests, fields, rocky hillsides and residential areas. They are often observed as they bask on rocks, wood piles, stone walls, hedges and swimming pool decks. Although they feed on a variety of small animals, garter snakes' primary prey are earthworms and amphibians. Their saliva appears to be toxic to amphibians and other small animals and a bite may produce swelling or a burning rash in some people. Although garter snakes may or may not bite if handled, most individuals secrete a foul-smelling fluid from anal glands when alarmed. Occasionally, garter snakes make their way into basements, a situation that appears to be most common in spring or autumn.



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