Common Garter Snake
Thamnophis sirtalis • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: T. sirtalis
North America, widely distributed from southern Canada down through the United States to the Gulf of Mexico, excluding parts of the arid Southwest.
Look up Common 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, with stable populations across most of its native range, though localized populations face habitat loss and road mortality.
Physical Description
Displays a checkered dorsal pattern with alternating dark spots and longitudinal striping visible along the body. The head is distinct with a dark crown, pale labial scales, and a round-pupiled eye.
Size & Dimensions
Estimated specimen length is approximately 45 to 60 cm. Adult typical length ranges from 46 to 130 cm.
Habitat
Found in a diverse range of habitats including forests, fields, marshes, grasslands, and suburban backyards, typically near sources of standing or slow-moving water.
Diet & Feeding
Feeds on a wide variety of small prey including amphibians, earthworms, fish, and small rodents, primarily utilizing active foraging techniques.
Reproduction
Viviparous, giving birth to live young. Mating typically occurs in the spring shortly after emerging from hibernation, with litters ranging widely from 10 to 40 or more offspring.
Look-alikes
Frequently confused with other garter snake species (Thamnophis spp.) and ribbon snakes (Thamnophis saurita), distinguished primarily by scale counts, exact stripe placements, and head markings.
Conservation Status
IUCN Red List status is Least Concern, with stable populations across most of its native range, though localized populations face habitat loss and road mortality.
Cultural Significance
A familiar and ecologically important predator of garden pests and amphibians, frequently featured in educational programs and suburban encounters across North America.
Notable Features
Exhibits excellent adaptability to human-altered environments and relies on specialized defensive behaviors such as musk secretion and erratic fleeing when threatened.