Common Garter Snake
Thamnophis sirtalis • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis
Widely distributed across North America, ranging from Nova Scotia and southern Canada down through the United States to the Gulf of Mexico and into parts of northeastern 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
IUCN Red List status is Least Concern, due to its exceptionally wide distribution, adaptability to human-altered environments, and large stable populations.
Physical Description
Slender body with a pattern of longitudinal light stripes running down the length of a darker brown, olive, or blackish background. Alternating rows of dark spots are often visible between the stripes. The head is relatively narrow and distinct from the neck, featuring keeled scales.
Size & Dimensions
The specimen shown appears to be a sub-adult or small adult, roughly 45 to 60 cm in length. Adults typically range from 46 to 130 cm total length.
Habitat
Found in a diverse range of habitats including forests, fields, marshes, prairies, and agricultural lands, typically near a permanent or temporary water source such as ponds, lakes, streams, and ditches.
Diet & Feeding
Diet consists primarily of amphibians (frogs, toads, salamanders), earthworms, and small fish. They actively forage for prey using both keen eyesight and a well-developed sense of smell.
Reproduction
Viviparous (gives birth to live young). Mating occurs in the spring shortly after emerging from hibernation, and females give birth to litters ranging from 10 to 40 or more live young in the late summer.
Look-alikes
Frequently confused with other garter snake species (Thamnophis spp.) and ribbon snakes (Thamnophis saurita). Distinguished by scale counts, stripe placement, and specific labial scale markings.
Conservation Status
IUCN Red List status is Least Concern, due to its exceptionally wide distribution, adaptability to human-altered environments, and large stable populations.
Cultural Significance
Commonly encountered in suburban and rural backyards across North America, often serving as an introductory species for people learning about local wildlife and reptile conservation.
Notable Features
Exhibits great color polymorphism across its range, with some populations showing bright red or blue flecking between stripes, and possesses a specialized resistance to the toxins found in the skin of some of its amphibian prey.