Description: Idaho’s two species of garter snakes are striped, slender snakes ranging in length from 18 inches and 4 feet. The Western terrestrial garter snake is brown or dark gray, with a dull yellow or brown stripe down the middle of its back. The common garter snake is black with red blotches and three stripes: a bright yellow one down the middle of its back and a buff or yellow one down either side.
Native habitat: Common garter snakes are found statewide, typically near water but also in open meadows and evergreen forests. Western terrestrial garter snakes frequent Idaho’s streams, lakes, and marshes as well as its desert riparian areas, mountain lakes, and mountain meadows.
Behavior: Adult garter snakes eat toads, frogs, and salamanders. The more varied diet of the Western terrestrial garter snake can also include fish, slugs, worms, small mammals, and lizards. In your yard, you may find garter snakes hunting for prey near water features or in high grass or other tall vegetation. They take shelter under logs, boards, rocks, and other debris.
Managing conflicts: Garter snakes are harmless. Left alone, they can help you manage rodent populations. If you believe they’re taking an unacceptable toll on other wildlife in your garden, take steps to reduce your yard’s attractiveness to snakes.
How to make your yard less attractive to snakes
- Remove logs, boards, rocks, rotten stumps, leaf and mulch piles, and other potential shelters and hiding areas.
- Discourage rodents and other food sources by keeping grasses mowed.
- Stack firewood at least 1 foot above the ground.
- Prune shrubbery at least 1 foot above the ground and away from foundations.
- Close off access to niches beneath storage sheds by packing soil and installing 1/4-inch or smaller hardware cloth 6 inches deep.
- Note: No chemical poisons or fumigants have been registered for snake control in Idaho, and no repellents have been proven effective.
Ways to manage nonpoisonous snakes can be found in the chapter, Nonpoisonous Snakes, found in Prevention and Control of Wildlife Damage.