Northwestern Garter Snake
Jacob A. R. Berg (2001)

Thamophis ordinoides

The Northwestern Garter Snake is an inhabitant of Southwestern British Columbia, Western Washington, Western Oregon, and the very Northwestern tip of California. They are usually 38 to 66 centimeters in length. They have the most variable scalation of any snake in the Northwest which makes it difficult to identify them. They usually have a vertebral line of a lighter color but it can be broken or absent. Color is not an easy tool to use to identify these snakes either as they are the most variable snake in Washington or Oregon with respect to color. Their body can be brown, greenish, bluish, or black and the vertebral line can be red, orange, yellow, or white. Side stripes are often common down the second and third scale rows, but this can also be absent or faint. The sides are occasionally dark spotted and the ventral side is usually yellow or gray and often with red splotches. This polymorphism in the way of coloration is probably to help the snake escape and hide from predators. The characteristic that makes it easiest to identify the Northwestern Garter Snakes from its close counterparts is its relatively small head. Garter snakes in general can be seperated from their close neighbors of water snakes by the fact that garter snakes have and undivided anal scute.

As far as the specimen I examined went, it was dark gray with a faint bluish tinge. It had a white vertebral line and white broken stripes on the second scale row. The belly was a cream color and no red splotches were observed. The cloaca was observed and is identified by an arrow in the picture above in the ventral view. The snake was 38 centimeters in length with a width and height of a maximum of two centimeters. These measurements lead me to assume that my specimen may have been a juvenile. It is important to note, however, that the head was half the width and height of the largest part of the snake’s body. Like all snakes, the scales all pointed posteriorly and they were long flat scales on the ventral side and many small scales on the dorsal.

The Northwestern Garter Snake is diurnal and most active on sunny days. It finds safety in the underbrush but rarely, if ever, is found in deep forests. They are primarily terrestrial, but may be found near water. They can often be found basking. Pregnant, shedding, or digesting snakes are especially likely to bask.

Breeding occur during March through April and sometimes from September to October. Ovulation occurs in May or June and gestation lasts for about nine weeks. The typical amount of young is six to eleven although it can range between three to twenty.

Thamnophis ordinoides feeds on frogs, salamanders, slugs, and worms. When encountered by a predator, the striped variety typically flees right away for the underbrush while the spotted variety will freeze. The typical predators of the Northwestern Garter Snake are Red-Tailed Hawks, Robins, Spotted owls, and Stellar’s Jays.

It is reasonably safe to handle the Northwestern Garter Snake. They are non-venemous and hardly ever bite. They may release uric acid and feces from their cloaca in response to handling though. It’s a small price to pay to handle one of the pacific Northwest’s often overlooked gems. Luckily, the Northwestern Garter Snake is not in danger of endangerment or extinction. It is not a pest but still not the best helper to the common American. Northwestern Garter Snakes do make nice pets though. It is snakes like Thamnophis ordinoides that give snake lovers a reason to love.

Grzimek, Dr. Dr. h.c. Bernard. Grzimek’s Animal Life Encyclopedia: Volume 6: Reptiles. Van Nostrand Reinhold Company. 1975. p 395

Behler, John L. and Kind, F. Wayne. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, Inc. 1975. p 669-670

Storm, Leonard, Brown, Bury, Darda, Diler, and Peterson. Reptiles of Washington and Oregon. Seattle Audubon Society. 1995. p 144-146