Common Garter Snake (Melanistic / Dark morph)
Thamnophis sirtalis • Order: Squamata, Suborder: Serpentes, Family: Natricidae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis
Widespread across North America, ranging from coast to coast in the United States, throughout southern and central Canada, and down into northern Mexico.
Look up Common Garter Snake (Melanistic / Dark morph) in the Snake Encyclopedia →Family
Order: Squamata, Suborder: Serpentes, Family: Natricidae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis
Conservation
IUCN Red List status: Least Concern (LC). Extremely abundant and resilient across its native range.
Physical Description
Dark charcoal-to-black ground color with a series of light beige or cream-colored checkered blotches and transverse bands along the dorsal and lateral fields. Heavily keeled dorsal scales. Dark head with round pupils and light labial/chin markings.
Size & Dimensions
Specimen shown is an adult or subadult, approximately 18 to 26 inches (45 to 65 cm) in length. Typical species size ranges from 18 to 36 inches (45 to 90 cm), with females generally larger than males.
Habitat
Extremely adaptable terrestrial to semi-aquatic species found in forests, fields, meadows, wetlands, marshes, agricultural areas, and suburban gardens, typically near a water source.
Diet & Feeding
Generalist predator feeding on earthworms, amphibians (toads, frogs, salamanders), fish, invertebrates, and occasionally small rodents or nestling birds. Uses active foraging and swallows prey alive.
Reproduction
Viviparous (gives birth to live young). Mating occurs in spring after emerging from brumation. Females give birth to litters ranging from 10 to 40+ live young in late summer.
Look-alikes
Can be confused with Northern Watersnakes (Nerodia sipedon) or Ribbon Snakes (Thamnophis saurita). Watersnakes are heavier-bodied with wider heads, while ribbon snakes are slimmer with prominent continuous longitudinal stripes.
Conservation Status
IUCN Red List status: Least Concern (LC). Extremely abundant and resilient across its native range.
Cultural Significance
One of the most familiar and ecologically beneficial snakes in North America, acting as an important natural pest control for garden invertebrates and serving as key prey for larger predators.
Notable Features
Exhibits significant color variation across its range, including melanistic and dark checkerboard morphs like this specimen. Possesses resistance to tetrodotoxin (TTX) found in toxic prey like newts.