Idaho’s diverse landscapes, from arid plains to mountain forests, support a variety of snake species. These reptiles are integral to the state’s natural ecosystems, contributing to biodiversity and playing a role in pest control. While the presence of snakes might cause concern for some, most species encountered in Idaho are not harmful to humans. Understanding these animals promotes coexistence and appreciation for their place in the environment.
Common Non-Venomous Snakes
Garter snakes are among Idaho’s most frequently observed non-venomous snakes, often found near water sources like streams, lakes, and marshes, though they also inhabit drier areas. The Western Terrestrial Garter Snake typically displays brown or dark gray coloration with a dull yellow or brown stripe, sometimes with black spots, while Common Garter Snakes are usually black with red blotches and three distinct stripes: a bright yellow dorsal stripe and a buff or yellow stripe on each side. These slender snakes generally range from 18 to 50 inches in length and are skilled swimmers. They primarily consume fish, frogs, tadpoles, earthworms, slugs, and small mammals. When threatened, garter snakes may release a musky scent.
Gopher snakes, also known as bullsnakes, are sizable non-venomous snakes in Idaho, potentially reaching up to 67 inches long. They have light brown or tan bodies with dark blotches, narrow heads, round pupils, and lack a rattle. These snakes inhabit warm, dry areas, including desert shrublands, farm fields, and forested regions across much of the state. Gopher snakes are active during the day, preying on rodents, rabbits, birds, and eggs. When disturbed, they may mimic rattlesnakes by hissing, flicking their tails, and flattening their heads, though they are harmless.
The Rubber Boa is a unique non-venomous snake in Idaho, distinguished by its loose, smooth skin that gives it a rubbery texture and a blunt tail resembling its head, leading to the nickname “two-headed snake.” These docile snakes are typically tan to dark brown or olive-green with lighter undersides, measuring between 18 and 33 inches. Rubber boas are largely nocturnal and elusive, favoring habitats with abundant cover such as rotting logs and rocks within grasslands, woodlands, and forests. They constrict their prey, which includes young mice, shrews, voles, lizards, and even other snakes.
North American Racers are slender, fast-moving snakes, observed gliding across dry terrain in lower elevations, foothills, and shrub habitats. Young racers are speckled brown, but mature into a solid greenish-gray with a yellow belly, typically reaching about 32 inches. Racers are diurnal, actively hunting insects, lizards, and other snakes during the day. Although non-venomous, they may bite repeatedly if cornered, a defensive behavior.
Idaho’s Venomous Rattlesnakes
Idaho is home to two species of venomous rattlesnakes: the Western Rattlesnake and the less common Prairie Rattlesnake. The Western Rattlesnake is the primary venomous species in southern and western Idaho. These pit vipers are identifiable by their distinctive tail rattle, triangular head, and heat-sensing pits. Their coloration varies (tan, brown, gray, or olive green) with dark blotches for camouflage in rocky, arid environments.
Adult Western Rattlesnakes measure between 2 and 5 feet. They inhabit a variety of environments, including sagebrush deserts, grasslands, forests, and rocky areas, and can be found at elevations up to 9,500 feet. While capable of swimming, rattlesnakes are primarily terrestrial. During hot summer months, they are often nocturnal, seeking refuge under bushes, rocks, or in crevices.
Rattlesnakes are ambush predators, using stealth and venom to subdue small mammals, birds, and lizards. When threatened, they typically coil and shake their rattle as a warning, though they may remain still to avoid detection. Rattlesnakes are not aggressive and prefer to avoid human interaction. Their rattle serves as an auditory deterrent.
Encountering Snakes Safely
Observing snakes can be rewarding, and precautions ensure safety. When hiking, remain on marked trails and be aware of surroundings. Wear over-the-ankle boots, thick socks, and loose-fitting long pants for protection. Avoid walking through tall grass or dense weeds where snakes might be concealed.
Exercise caution when placing hands or feet near rocks, logs, or brush piles to prevent accidental encounters. Inspect stumps, logs, or dark crevices before sitting or reaching into them. If a snake is sighted, maintain a respectful distance and allow it to move away undisturbed. Do not provoke, handle, or harm any snake, as bites often occur when they feel threatened.
In the rare event of a snake bite, seek immediate medical attention. Stay calm and call 911 immediately. While waiting, gently wash the bite area with soap and water, and remove any tight clothing or jewelry that might constrict swelling. Keep the affected limb still and, if possible, below heart level. Avoid applying a tourniquet, icing the wound, or attempting to suck out the venom, as these actions can cause further harm.
Snake bites are uncommon in Idaho, with an average of about 12 incidents reported annually, and fatalities are extremely rare.