Eastern Ribbon Snake – Thamnophis sauritus vs Common Garter Snake – Thamnophis sirtalis

Eastern Ribbon Snake – Thamnophis sauritus

Eastern Ribbon Snakes resemble Common Garter Snakes, but they are much more slender.  They are not as widely distributed as the Common Garter Snake.

Appearance:  Eastern Ribbon Snakes are slender and can be up to one meter in total length, although most individuals are smaller.  The tail is proportionally longer than in most other snake species.  The light stripe on the side is on the third and fourth scale rows, so a black line is present between the light-colored belly and the light side stripe.  In Eastern Ribbon Snakes there is a sharp boundary between the light colored lips and the dark upper part of the head; in Common Garter Snakes this boundary is blurred and less sharply defined.  The chin is light-colored and there is a yellow or white spot in front of the eye.  The scales of the back and sides are keeled.

Eastern Ribbon Snakes

Habitat and Behavior:  Eastern Ribbon Snakes prefer meadows or forest edges, and they are often found near the edges of permanent bodies of water such as marshes, ponds, lakes, and rivers.  They will readily enter the water and may see basking on offshore logs and rocks. They often feed in water, capturing frogs and fish, although they also eat insects, worms and other invertebrates.  In Ontario, they are much less widely distributed than the Common Garter Snake.

Reproduction:  Like their Common Garter Snake relative, Eastern Ribbon Snakes also give birth to live young.  Mating occurs in spring, and the young are born in midsummer.  The brood size is typically from 5 to 20.

Common Garter Snake – Thamnophis sirtalis

Although the Common Garter Snake is our most familiar reptile in Ontario, its variable colours and patterns can lead to mistaken identifications.

Appearance:  The maximum length is one metre,but adults do not usually exceed 24 inches.  The scales on the back and sides are keeled.  The dorsal background colour is black, and the belly is pale yellow or green, sometimes with two rows of dark spots.  The light colored stripe on the side is always on the second and third scale rows; this means that there is very little black background visible between the light stripe and the light colored belly. 


Common Garter Snake – Thamnophis sirtalis

The mid-dorsal light stripe can be yellow,brown, orange, or even red.  Some individuals may have a checkered pattern.  Some Common Garter Snakes are almost completely black with plain black bellies and white throats.  Black Common Garter Snakes are usually found only on the shore and islands of Lake Erie.

Habitat and Behavior:  The Common Garter Snake is the most widely distributed snake species in Ontario.  The preferred habitat is open areas such as meadows, often in suburban and even urban areas. Garter Snakes readily enter water to feed or to escape predators.  They eat insects, worms, small frogs, and fish.  When handled, this species may bite and release musk from glands at the base of the tail.  Common Garter Snakes hibernate underground, and large numbers may overwinter together in suitable locations.

Reproduction:  Common Garter Snakes do not lay eggs but bear their young live.  Mating occurs as soon as the snakes emerge from hibernation.  Females seek out sunny locations to raise their body temperature and speed embryonic development.  The young are born in July.

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