Thamnophis Ordinoides – Northwestern Garter Snake

Thamnophis Ordinoides - Northwestern Garter Snake dark brown snake with longitudinal stripes orange and yellow. Found in Oregon, washington and california

The northwestern garter snake is one of the smaller species of the harmless garter snakes. It is found in the Northwestern United States and neighboring Canada. Most commonly, the snake has a dark body with one or three lighter longitudinal stripes.

Description

The northwestern garter snake shows a very high variability in the basic coloration. Their body color ranged from shades of black, green, blue and brown to very light grey or beige. The snake always has a visible stripe along the center of its back. The stripe can come in a wide variety of colors (white, yellow, orange, red or blue-gray). It also has two lateral stripes that are lighter than the ground color, but they are not present in all specimens. The stripes of the northwestern garter snake are often thinner than the longitudinal stripes of other garter snake species. The iris is always black, the pupil is round.

Thamnophis Ordinoides - Northwestern Garter Snake dark brown snake with longitudinal stripes orange and yellow. Found in Oregon, washington and california
A Northwestern garter snake with orange and yellow stripes. Photo: Don Henise

Since its range overlaps with the common garter snake (Thamnophis sirtalis), which can also take on a wide variety of appearances with a central longitudinal stripe, the two species are often confused. Both species are harmless for humans.

Size

With an average size of 17-27 inches (40-70 cm), the Northwestern garter snake is one of the smallest garter snake species. Individual specimen can reach a length of up to 40 inches (100 cm). Adult females are considerably larger than males, often twice as long.

Northwestern garter snake juvenile held on hand harmless
A northwestern garter snake found in Oregon. Photo: Tom Brandt

Hunting Behavior and Habitat

The Northwestern garter snake prefers humid environments and is often found in marshlands or wet meadows at the edge of forest areas. The small snake feeds mainly on slugs and worms.

Bite

The northwestern garter snake is not a dangerous snakes for humans. Even though garter snakes produce a mildly venomous saliva, the toxines are not strong enough to cause any significant medical effects on humans or larger pets. Due to the size of the northwestern garter snake, a bite that pierces through human skin is rare. In the few cases where a bite occurs, it may cause an itching or burning sensation without any serious or long-term effects.

yellow and brown northwestern garter snake in oregon
A yellow and brown-grey Northwestern garter snake. Photo: Tom Brandt

Northwestern garter snake range in the USA

As its common name suggests, the Northwestern garter snake can be found in the Northwest of the United States and in Southwestern Canada. In the United States, the snake occurs in Western Washington, Western Oregon and Northwestern California.

Scientific classification of Thamnophis ordinoides

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Reptilia
  • Order: Squamata
  • Suborder: Serpentes
  • Family: Colubridae
  • Genus: Thamnophis
  • Species: Thamnophis ordinoides
Thamnophis Ordinoides – Northwestern Garter Snake

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