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Snakes

What is a snake doing in my yard?

It's probably just passing through, either foraging for food or traveling to and from its winter den. Nearby development may also have displaced it, so it may be temporarily "lost." Wildlife experts say that visiting snakes will generally be long gone before the experts can arrive at your home to identify or remove them. If yours is the unusual case where a snake is actually lingering, then it has found a reliable source of food, suitable shelter or both. Of the 12 species of snakes that live in Idaho, the four most likely to cross urban landscapes are:

  • Common garter snake (Thamnophis sirtalis)
  • Western terrestrial garter snake (Thamnophis elegans)
  • Gopher snake (Pituophis catenifer)
  • Western rattlesnake (Crotalus viridis)

Since 2005, all of Idaho's native snakes have been designated as Protected Nongame. That's because they fulfill a vital ecological role, eating rodents and other pests while serving as food for raptors, coyotes and even other snakes. (Note: Although rarely necessary, it's still legal to kill a snake to protect your personal health and safety and to manage your property.) Read on to learn more about each of these snakes and to decide how you'll respond to their presence on your property.

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.

Information courtesy of:

Description: Gopher snakes are predominantly tan or light brown, with three rows of dark brown or black blotches along their heavy bodies. Commonly called bullsnakes, they can be from 36 to 80 inches long and pose no danger to humans or pets. They use constriction and suffocation-rather than venom-to kill their prey. However, because the patterns on their backs are similar to rattlesnakes and because they coil, vibrate their tails and even strike when threatened, gopher snakes are often mistaken for rattlesnakes. Look for these differences:

  • Gopher snake tails taper to a thin tip and lack rattles; rattlesnake tails always have rattles (or immature buttons), unless the rattle has broken off.
  • Gopher snake heads are usually narrow, while rattlesnake heads are always triangular.
  • Gopher snake eyes have round pupils, while rattlesnake pupils are vertical.

When alarmed, gopher snakes make hissing or buzzing noises with their vibrating tails; rattlesnakes make rattling noises. Experts can readily tell the difference, but novices might not.

Native habitat: Gopher snakes can be found in all parts of the state except northern Idaho. Their very diverse habitats include desert shrub lands, low mountain areas and farm fields.

Behavior: Gopher snakes are generally active by day, preying on rodents, rabbits and birds. When the weather turns hot, they hunt during the night and rest — often on warm rocks or pavement — during the day. They hibernate during the winter and are out and about between April and October.

Managing conflicts: Voracious rodent-eaters that can chase their prey both above- and underground, gopher snakes will help you control your pest problems. Odds are you won't have their services for long because they're not likely to linger in your yard. If you're not certain whether your serpentine visitor is a gopher snake or rattlesnake, call in a description to a wildlife expert. If it's clearly a gopher snake and you spot it repeatedly, you can choose to either let it be or take steps to reduce your yard's attractiveness to snakes. Ways to manage nonpoisonous snakes can be found in the chapter, Nonpoisonous Snakes, found in Prevention and Control of Wildlife Damage.

Information courtesy of:

  • Idaho Museum of Natural History Digital Atlas, Gopher Snake
  • "Idaho's Amphibians and Reptiles," Nongame Wildlife Leaflet #7, Idaho Department of Fish and Game

Description: Western rattlesnakes have large, triangular heads, narrow necks and dark brown or black blotches on lighter backgrounds. They can be up to 65 inches long. Unless they're newborn or have been injured, all have rattles at the ends of their short tails. Rattlesnakes kill their prey by injecting venom via two large fangs and then swallowing them whole. Three subspecies (Prairie, Great Basin and Northern Pacific) live in Idaho. They differ mostly in their color patterns, which typically resemble their environments.

Native habitat: Western rattlesnakes are found throughout Idaho, except at high elevations and in the northern part of the state. They prefer dry, rocky areas with sparse vegetation.

Behavior: Western rattlesnakes eat mostly mice, ground squirrels and rabbits. They are active from March to November, generally hunting throughout the day in moderate temperatures but preferring the earlier and later hours during the warm summer months. They seek their prey in or near tall grass, rodent burrows, rock outcrops, surface objects or in the open and they take shelter in crevices, caves, mammal burrows and sometimes dense vegetation.

Managing conflicts: Western rattlesnakes are rarely found in Idaho yards, but homeowners living at the urban-rural interface may occasionally see one. Be aware that well-camouflaged rattlesnakes may be waiting quietly for prey in rock crevices, under logs, in heavy brush or even in tall grass, so be careful where you put your hands and feet. If you hear or see a rattlesnake, move slowly away from it. Few people are bitten by rattlesnakes in Idaho. Although pets have died, no human fatalities have been recorded. You should consider asking for assistance from a wildlife biologist or pest management professional if rattlesnakes are frequenting your yard. Plan to take steps to reduce your yard's attractiveness to snakes.

Information courtesy of:

  • University of California IPM Online, Rattlesnakes
  • Idaho Museum of Natural History Digital Atlas, Western Rattlesnake
  • "Idaho's Amphibians and Reptiles," Nongame Wildlife Leaflet #7, Idaho Department of Fish and Game

University of Idaho Extension

Physical Address:
E. J. Iddings Agricultural Science Laboratory, Room 52
606 S Rayburn St.
Moscow, ID

Mailing Address:
University of Idaho Extension
875 Perimeter Drive MS 2338
Moscow, ID 83844-2338

Phone: 208-885-5883

Fax: 208-885-6654

Email: extension@uidaho.edu

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Barbara Petty