Common Garter Snake (Red-spotted subspecies)
Thamnophis sirtalis concinnus • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis
This specific subspecies is found primarily in the Pacific Northwest of the United States, specifically Western Oregon and Southwest Washington. The broader species ranges across nearly all of North America.
Look up Common Garter Snake (Red-spotted subspecies) in the Snake Encyclopedia →Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Thamnophis, Species: Thamnophis sirtalis
Conservation
IUCN Least Concern. Highly adaptable to human-altered landscapes, though local populations suffer from habitat loss and pesticide use.
Physical Description
Black ground color with a distinct bright yellow or greenish dorsal stripe. Lateral red spots or blotches are prominent between the dorsal and lateral stripes. Head is typically dark with a pale upper lip and round pupils. Scales are strongly keeled.
Size & Dimensions
The specimen appears to be an adult, approximately 18-24 inches. The species average is 18 to 36 inches (46–91 cm); maximum recorded length is about 54 inches.
Habitat
Generalist species often found near water sources like ponds, streams, and marshes. They inhabit meadows, forest edges, and suburban gardens. Found from sea level to moderate mountain elevations.
Diet & Feeding
Generalist carnivore. Consists of earthworms, slugs, amphibians (frogs, toads, salamanders), fish, and occasionally small mammals or birds. They use active foraging rather than ambush.
Reproduction
Viviparous (gives birth to live young). Litters typically range from 10 to 40 neonates, born in late summer or early autumn.
Look-alikes
Northwestern Garter Snake (Thamnophis ordinoides) which is smaller with more varied colors, and the Western Terrestrial Garter Snake (Thamnophis elegans) which has different facial markings.
Conservation Status
IUCN Least Concern. Highly adaptable to human-altered landscapes, though local populations suffer from habitat loss and pesticide use.
Cultural Significance
One of the most commonly encountered snakes in North America. They play a vital ecological role in controlling pest populations like slugs and insects in gardens.
Notable Features
Remarkable for their resistance to tetrodotoxin (TTX) found in Pacific Newts, allowing them to prey on toxic amphibians that would kill other predators.