Garter Snake
Thamnophis sirtalis • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: T. sirtalis
Widely distributed throughout North America, ranging from Nova Scotia and southern Canada down through the United States to the Gulf of Mexico and parts of Florida, extending into northeastern Mexico.
Look up Garter Snake in the Snake Encyclopedia →Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: T. sirtalis
Conservation
IUCN Red List status is Least Concern. While widespread and generally abundant, populations can face local declines due to habitat loss, road mortality, and deliberate persecution.
Physical Description
Features a prominent yellowish or whitish vertebral (mid-dorsal) stripe running down the length of its body, accompanied by lateral stripes on each side. The dorsal background is typically dark brown, olive, or black, interspersed with alternating rows of dark spots or checkers. Scales are keeled, providing a somewhat textured appearance.
Size & Dimensions
Estimated specimen length is approximately 60-75 cm. Typical adult size ranges from 46 to 130 cm (18 to 51 inches) in total length, varying by subspecies and region.
Habitat
Highly adaptable, found in a wide variety of habitats including grasslands, woodlands, marshes, drainage ditches, agricultural fields, and suburban backyards, typically near permanent or temporary sources of water.
Diet & Feeding
Diet consists primarily of amphibians (frogs, toads, salamanders), earthworms, small fish, and occasionally small mammals, birds, or reptiles. Active foragers relying heavily on keen senses of smell and tongue-flicking to locate prey.
Reproduction
Viviparous (gives birth to live young). Mating typically occurs in the spring shortly after emerging from brumation. Females give birth to litters ranging from 10 to 40 or more live young in mid-to-late summer.
Look-alikes
Frequently confused with other garter snake species (Genus Thamnophis) such as the Ribbon Snake (Thamnophis saurita) which is typically more slender with longer tails, or various species of grass snakes and lined snakes, distinguished by exact scale counts and stripe arrangements.
Conservation Status
IUCN Red List status is Least Concern. While widespread and generally abundant, populations can face local declines due to habitat loss, road mortality, and deliberate persecution.
Cultural Significance
Commonly encountered in suburban gardens and agricultural areas where they serve as beneficial predators of garden pests like slugs and insects. Frequently kept as educational animals or pets due to their hardiness.
Notable Features
Exhibits communal brumation (overwintering) where dozens or even hundreds of individuals may gather in underground dens, and males emerge en masse in spring to court newly emerged females in mating balls.