Common Garter Snake
Thamnophis sirtalis • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis
Widespread across North America, ranging from southern Canada south through most of the continental United States into northern Mexico.
Look up Common Garter Snake in the Snake Encyclopedia →Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis
Conservation
Least Concern (IUCN Red List). Abundant and stable across most of its range, though local populations suffer from habitat destruction and road mortality.
Physical Description
Features three distinct light yellow or whitish longitudinal stripes (one dorsal, two lateral) running over a dark brownish-black ground color. Interspaces display a chequered dark pattern on expanded interstitial skin. Head is distinct from neck with large eyes and round pupils. Dorsal scales are keeled.
Size & Dimensions
Specimen pictured is an adult measuring around 18-24 inches (45-60 cm). Species average size ranges from 18 to 26 inches (45 to 65 cm), with maximum recorded lengths up to 49 inches (124 cm).
Habitat
Highly adaptable, commonly found in meadows, marshes, woodlands, fields, suburban gardens, parks, and near body edges like streams and ponds, up to moderately high elevations.
Diet & Feeding
Generalist predator feeding mainly on amphibians (frogs, toads, salamanders), earthworms, slugs, small fish, and occasionally small rodents or nestling birds. Swallows prey alive without constriction.
Reproduction
Viviparous (gives birth to live young). Mating occurs in early spring after emerging from brumation. Litters average 10 to 40 live young, typically born between mid-summer and early autumn.
Look-alikes
Commonly confused with Ribbon Snakes (Thamnophis saurita / T. proximus), which are more slender with lateral stripes strictly on scale rows 3 and 4, and Gopher/Bullsnakes or Dekay's Brownsnakes (Storeria dekayi).
Conservation Status
Least Concern (IUCN Red List). Abundant and stable across most of its range, though local populations suffer from habitat destruction and road mortality.
Cultural Significance
One of North America's most recognizable, familiar, and culturally iconic garden snakes. Plays a critical ecological role controlling agricultural and garden pests such as slugs and rodents.
Notable Features
Distinguished by its ability to safely consume toxic prey like rough-skinned newts and common toads due to a high resistance to tetrodotoxin (TTX) and bufotoxins.