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Reptiles of Washington


Northwestern garter snake
(Thamnophis ordinoides)

 

What they look like

  • Northwestern garter snakes barely reach 34 inches in length and are the smallest garter snake species in Washington.
  • They are some of the most variable snakes in terms of coloration and pattern, so not all individuals will match these following general descriptions.
  • Most are brown or black with three stripes along the length of their body. Some possible stripe colors include white, yellow, green, turquoise, and blue. Sometimes small dark spots are seen near the stripes. Their underside usually starts out white or yellow near the head and becomes more blue or black near the tail.

Where they live

  • Northwestern garter snakes can be found in British Columbia, Washington, Oregon, and California.
  • They are the most terrestrial garter snake in Washington and prefer to live in spacious open habitats, including open grassy areas, forest openings, and edges of coniferous forests, especially near bodies of water.

What they eat

  • Northwestern garter snakes primarily feed on slugs and earthworms, although amphibians, snails, and fish can also be eaten.

Breeding

  • Between late summer and early fall, females gather in open grassy areas to give live birth.
  • Number of young born can vary dramatically, usually from 3 to 80 snakes.

Cool Biology Facts

  • The record for greatest number of young northwestern garter snakes born in a single litter is 98!
  • As many as 25 male northwestern garter snakes have been known to compete for a single female during breeding season! 

Photo

Distribution Map

Threats

Northwestern garter snakes are common in western Washington. They are considered “least concern” due to their widespread distribution and large stable populations.