Common Garter Snake
Thamnophis sirtalis • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: T. sirtalis
North America, widely distributed throughout the United States, Canada, and parts of Mexico, inhabiting nearly every state and province.
Look up Common Garter Snake in the Snake Encyclopedia →Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: T. sirtalis
Conservation
Evaluated as Least Concern by the IUCN Red List due to its exceptionally wide distribution, large overall population, and adaptability to human-altered environments.
Physical Description
Dark brown to blackish body with visible longitudinal pale stripes running down the back and sides. The head is slightly distinct from the neck, eyes have round pupils, and the body appears slender with keeled scales.
Size & Dimensions
The visible specimen appears to be approximately 45 to 60 cm in length. Typical adults range from 46 to 130 cm in total length, with females generally growing larger than males.
Habitat
Found in a diverse range of habitats including forests, fields, marshes, prairies, and suburban backdoors, typically near water sources such as ponds, lakes, streams, and ditches.
Diet & Feeding
Diet consists of amphibians, earthworms, small fish, slugs, and occasionally small mammals or birds. They are active foragers that rely primarily on keen eyesight and a sensitive tongue-flicking mechanism to locate prey.
Reproduction
Viviparous (giving birth to live young). Mating occurs typically in the spring shortly after emerging from hibernation, with females producing litters ranging from 10 to 40 or more young in mid-to-late summer.
Look-alikes
Frequently confused with other natricine snakes like ribbon snakes (Thamnophis saurita) which have more slender builds and longer tails, or various species of water snakes (Nerodia) which tend to be heavier-bodied and possess distinct patterns.
Conservation Status
Evaluated as Least Concern by the IUCN Red List due to its exceptionally wide distribution, large overall population, and adaptability to human-altered environments.
Cultural Significance
Often encountered in suburban yards where they serve as natural controllers of garden pests such as slugs, snails, and rodents. They are frequently utilized in educational settings due to their mild disposition.
Notable Features
Exhibits a high degree of color and pattern variation across its extensive geographic range. Many populations possess specialized immunity or resistance to the toxins found in certain prey species like rough-skinned newts.