Common Garter Snake
Thamnophis sirtalis • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: T. 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 northern Mexico.
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 extremely wide distribution, high adaptability, and large overall population numbers, though local populations face threats from habitat fragmentation and road mortality.
Physical Description
Displays dark brownish-gray to black dorsal coloration with distinct longitudinal striping, heavily keeled dorsal scales giving a textured appearance, and pale scale margins creating a checkered or speckled pattern.
Size & Dimensions
Specimens typically range from 46 to 137 cm (18 to 54 inches) in total length, with adult females generally growing larger than males.
Habitat
Found in a diverse array of habitats including grasslands, woodlands, marshes, agricultural fields, and suburban backyards, typically near permanent or temporary sources of water.
Diet & Feeding
Generalist carnivore feeding on amphibians, earthworms, small fish, and occasionally mice or other small reptiles, employing an active foraging strategy.
Reproduction
Viviparous (giving birth to live young), with mating occurring primarily in the spring shortly after emerging from brumation, resulting in litters typically ranging from 10 to 40 offspring.
Look-alikes
Frequently confused with other natricine snakes such as ribbon snakes (Thamnophis saurita) and various water snakes (Nerodia species), distinguished primarily by specific dorsal and lateral stripe placements and scale counts.
Conservation Status
Listed as Least Concern on the IUCN Red List due to its extremely wide distribution, high adaptability, and large overall population numbers, though local populations face threats from habitat fragmentation and road mortality.
Cultural Significance
Serves as an important ecological predator helping to regulate amphibian and invertebrate populations, and is frequently utilized in educational settings and scientific research due to its adaptability.
Notable Features
Known for participating in massive communal brumation sites where hundreds or thousands of individuals overwinter together, emerging in dense mating balls in the spring.