Common Garter Snake
Thamnophis sirtalis • Kingdom: Animalia, Phylum: Chordata, Class: Reptilia, Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: T. sirtalis
North America, ranging from southern Canada through most of the United States down to northern Mexico, inhabiting diverse biomes from forests and fields to wetlands.
Look up Common Garter Snake in the Snake Encyclopedia →Family
Kingdom: Animalia, Phylum: Chordata, Class: Reptilia, Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: T. sirtalis
Conservation
IUCN Red List status is Least Concern, facing local threats primarily from habitat loss, road mortality, and intentional killing.
Physical Description
Characterized by three distinct longitudinal light stripes (a vertebral dorsal stripe and two lateral stripes) running down a dark body, with checkered or spotted patterns between the stripes. Scales are keeled, and the head is slightly distinct from the neck with round pupils.
Size & Dimensions
Specimen is estimated at around 20 to 30 inches; typical adult size ranges from 18 to 54 inches in total length.
Habitat
Highly adaptable, found near water sources such as marshes, lakes, streams, and ponds, but also in meadows, woodlands, and agricultural fields, from sea level up to elevations of over 8,000 feet.
Diet & Feeding
Active forager feeding on a wide variety of prey including amphibians, earthworms, fish, small mammals, and insects, subduing prey live without constriction.
Reproduction
Viviparous (giving birth to live young), with litters typically ranging from 10 to 40 offspring, born in late summer after mating in the spring following brumation.
Look-alikes
Frequently confused with other ribbon snakes and garter snake species (such as the Butler's garter snake or Western ribbon snake), distinguished by the exact placement of lateral stripes on specific scale rows.
Conservation Status
IUCN Red List status is Least Concern, facing local threats primarily from habitat loss, road mortality, and intentional killing.
Cultural Significance
Commonly featured in educational programs and popular culture as a backyard reptile, serving an important ecological role in controlling amphibian and insect populations.
Notable Features
Exhibits communal brumation where hundreds of individuals gather in underground dens over winter, and possesses a specialized resistance to the toxins of certain amphibian prey.