Snakes in Colorado

Colorado is home to about 40+ species of snakes, and only 3 of them are venomous. All 3 are rattlesnakes. There are no copperheads or cottonmouths in Colorado or anywhere in the far West, so a venomous snake here always means a rattlesnake. The remaining 38 species are harmless to people, and across most of the state the only one you realistically need to recognize is the Prairie Rattlesnake.

Colorado is split down the middle by the Rocky Mountains, and that shapes everything about its snakes. The eastern plains and foothills are dry shortgrass prairie and rolling grassland, prime rattlesnake country. The high mountains in the center of the state are cold and elevated enough that snakes thin out fast and disappear above the foothills; you will not find rattlesnakes up in the alpine. The western slope drops into canyon and sagebrush country with its own desert-edge species. So the snakes cluster on the warm low ground east and west and largely skip the high middle.

Colorado records 3 venomous kinds, all rattlesnakes. The Prairie Rattlesnake is by far the most common and widespread, ranging across the eastern plains, foothills, and grasslands and into the western valleys. The Western Rattlesnake (in its midget faded form) lives in the canyon and sagebrush country of the western slope. The Western Massasauga is a small, secretive rattlesnake of the far southeastern sandhills and grassland, rare and seldom seen. Outside the plains and the western canyons, encounters with any of them are uncommon.

Most snakes Coloradans actually see are harmless. Gophersnakes (often called bullsnakes here) are big, common, and famous bluffers, hissing loudly and buzzing their tails to imitate a rattlesnake even though they have no venom and no rattle. Kingsnakes eat rattlesnakes and resist their venom. Garter snakes stay near streams and ponds, racers and coachwhips streak across the plains, and the hognose snake plays dead and puts on a dramatic hissing display when bothered. Honest safety: nearly every serious snakebite in Colorado is a rattlesnake bite, and most happen when someone handles, corners, or surprises a snake or reaches into rock and brush blindly. Deaths are very rare with antivenom and prompt care. Give rattlesnakes space and watch your hands and feet on the prairie and rocks. Never handle a wild snake, and if a bite happens, call Poison Control at 1-800-222-1222 or 911.