Snake Identifier
Common Garter Snake

Common Garter Snake

Thamnophis sirtalisOrder: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis

Widely distributed throughout North America, ranging from subarctic regions of Canada to the Rio Grande in Texas and from the Atlantic to the Pacific coasts.

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Family

Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis

Conservation

IUCN Red List: Least Concern. Highly adaptable and abundant throughout most of its range.

Physical Description

Small to medium snake with three longitudinal stripes (one dorsal, two lateral) which can be yellow, white, or green. The background color is dark green to black with a checkered pattern of dark spots. Scales are keeled; head is slightly wider than the neck; eyes have round pupils.

Size & Dimensions

The specimen appears to be an adult approximately 50-70 cm in length. Typical adult size for the species ranges from 46 to 137 cm.

Habitat

Extremely versatile, found in meadows, marshes, woodlands, and suburban gardens. They prefer areas near water sources and are found from sea level to high alpine meadows.

Diet & Feeding

Highly varied diet including earthworms, amphibians (frogs, toads, salamanders), fish, and occasionally small rodents or birds. They are active hunters that swallow prey alive.

Reproduction

Ovoviviparous (gives birth to live young). Mating occurs in spring shortly after emerging from hibernation; females give birth to 10-40 young in late summer.

Look-alikes

Ribbon Snakes (Thamnophis saurita) which are more slender with stripes on different scale rows; Water Snakes (Nerodia spp.) which are heavier-bodied and lack the distinct dorsal stripe.

Conservation Status

IUCN Red List: Least Concern. Highly adaptable and abundant throughout most of its range.

Cultural Significance

One of the most commonly encountered snakes in North America, playing a vital role in controlling pest populations and as a key species in backyard ecosystems.

Notable Features

One of the most cold-tolerant snake species in the world, capable of surviving in the far north of Canada where other reptiles cannot exist. They are known to hibernate in large communal dens called hibernacula.

Identified on 6/16/2026