Common 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 Florida.
Look up Common Garter Snake in the Snake Encyclopedia →Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: T. sirtalis
Conservation
Listed as Least Concern on the IUCN Red List due to its extensive geographic distribution, broad ecological tolerance, and large overall population size, though local populations face habitat fragmentation.
Physical Description
Features a brownish-olive dorsal background with distinct dark spots or blotches alternating along the flanks. A prominent yellowish-tan vertebral stripe runs down the center of the back. The head has distinct vertical dark labial bars along the lip scales, and the eyes feature round pupils. Scales are keeled, giving a textured appearance.
Size & Dimensions
The pictured specimen appears to be an adult or sub-adult measuring approximately 50 to 60 cm. Typical total length for the species ranges from 46 to 130 cm, with females generally growing larger than males.
Habitat
Found in a diverse array of habitats including forests, fields, marshes, prairies, and suburban backwaters. Often associated with permanent or temporary water bodies, but can also inhabit relatively dry terrestrial zones.
Diet & Feeding
Diet consists primarily of amphibians (frogs, toads, salamanders), earthworms, small fish, and occasionally small rodents or birds. They are active daytime foragers that rely primarily on sight and chemoreception to locate prey.
Reproduction
Viviparous species, giving birth to live young rather than laying eggs. Mating typically occurs in the spring shortly after emerging from hibernation, with litter sizes ranging from 10 to 40 or more young.
Look-alikes
Frequently confused with other ribbon snakes or garter snake species (such as the Plains Garter Snake or Butler's Garter Snake). Distinguished by the precise placement of lateral stripes, labial bar patterns, and head shape.
Conservation Status
Listed as Least Concern on the IUCN Red List due to its extensive geographic distribution, broad ecological tolerance, and large overall population size, though local populations face habitat fragmentation.
Cultural Significance
Commonly encountered in suburban areas across North America, often serving as an introductory species for people learning about local wildlife and playing an important role in controlling amphibian and insect populations.
Notable Features
Exhibits a wide array of color morphs and pattern variations across its vast geographic range. Known for exuding a foul-smelling musk from cloacal glands when captured or heavily startled.