Common Garter Snake (Checkered/Spotted Variant)
Thamnophis sirtalis • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis
Widely distributed throughout North America, ranging from the subarctic regions of Canada to the Southern United States, and from the Atlantic to the Pacific coast.
Look up Common Garter Snake (Checkered/Spotted Variant) in the Snake Encyclopedia →Venomous Status
Non-venomous (though they possess a Duvernoy's gland that produces a mild secretion not harmful to humans; they lack specialized fangs).
Danger Level
Harmless; they are not aggressive and their primary defense is flight or musking rather than biting.
Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis
Conservation
Least Concern (IUCN). They are one of the most common and widespread snake species in North America, though local populations can be affected by pesticide use and habitat loss.
Physical Description
Slender body with a yellowish-tan base color. It features a prominent light-colored dorsal stripe and a checkered pattern of dark spots between the stripes. The head is distinct from the neck with large eyes and round pupils. Scales are keeled.
Size & Dimensions
This specimen appears to be an adult, approximately 60-70 cm (24-28 inches). The species typically ranges from 46 to 137 cm (18 to 54 inches).
Habitat
Extremely versatile, found in forests, fields, prairies, and suburban gardens. They are often found near water sources like marshes, lakes, or streams. This specimen is in a landscaped garden area (mulch and shrubs).
Behavior & Temperament
Diurnal and active forager. When threatened, they may flatten their heads, strike defensively, or release a foul-smelling musk from the cloaca. Generally docile compared to other water-snake relatives.
Diet & Feeding
Generalist carnivores that feed on earthworms, slugs, frogs, toads, salamanders, fish, and occasionally small rodents. They use their sense of smell to track prey and swallow it alive.
Reproduction
Ovoviviparous (gives birth to live young). Late summer litters usually consist of 10 to 40 young, though larger litters are possible. Mating occurs in spring shortly after emerging from brumation.
Venom Profile
Non-venomous - no medically significant venom. Secretions may cause mild localized swelling in rare cases of prolonged bites.
Look-alikes
Often confused with Ribbon Snakes (Thamnophis saurita) which are thinner with higher-placed lateral stripes, or Water Snakes (Nerodia sirtalis) which have thicker bodies and lack the distinct dorsal stripe.
Conservation Status
Least Concern (IUCN). They are one of the most common and widespread snake species in North America, though local populations can be affected by pesticide use and habitat loss.
Cultural Significance
Commonly encountered in North American backyards, they serve as vital pest controllers by eating slugs and insects. They are a staple of environmental education and frequently a child's first encounter with a wild snake.
Notable Features
This specific individual exhibits a very prominent 'checkerboard' pattern on the flanks and a bright yellowish labial/neck area, showing the high degree of color polymorphism within the species.