Colorado is home to a diverse array of wildlife, including various snake species. While most snakes encountered in the state are harmless, it is important to be aware of the few venomous species present. Understanding these snakes and their behaviors can help ensure safety for both residents and visitors enjoying Colorado’s natural environments.
Venomous Snake Species in Colorado
Colorado hosts three venomous snake species, all of which are rattlesnakes: the Prairie Rattlesnake, the Midget Faded Rattlesnake, and the Massasauga. The Prairie Rattlesnake (Crotalus viridis) is the most widespread and largest of these, reaching lengths between 3.3 and 5 feet. Its coloration can vary, including shades of greenish-gray, olive green, light brown, or yellow, often with dark blotches along its back that become rings near the tail. These snakes inhabit diverse environments across the state, from open prairies and grasslands to semi-desert shrublands and forested areas, even at elevations up to 9,500 feet.
The Midget Faded Rattlesnake (Crotalus concolor), a subspecies of the Western Rattlesnake, is smaller than the prairie rattlesnake, measuring two to 2.5 feet long. This species is found in west-central Colorado, within the Colorado and Green River basins, preferring rocky hillsides and sagebrush habitats. While smaller, its venom is potent, containing both neurotoxins that affect the nervous system and myotoxins that damage muscle tissue. The Massasauga (Sistrurus catenatus) is the smallest venomous snake in Colorado, growing to 14 to 36 inches in length. This rattlesnake is restricted to the southeastern grasslands of Colorado, particularly in counties like Lincoln, Bent, and Prowers, at elevations below 5,500 feet.
Recognizing Venomous Snakes
Identifying venomous snakes in Colorado involves looking for several distinguishing characteristics. Rattlesnakes possess a triangular-shaped head, which is noticeably wider than their neck. Their pupils are vertical and elliptical, resembling a cat’s eye, particularly in bright light, in contrast to the round pupils of most non-venomous snakes.
Another key feature is the presence of heat-sensing pits located between their nostrils and eyes, which are used to detect prey. The most recognizable sign is the rattle at the end of their tail, composed of interlocking keratin segments that produce a distinct buzzing or rattling sound when vibrated. However, a rattlesnake may not always rattle, or its rattle might be damaged, so relying on sound alone is not sufficient for identification.
Safe Encounters and Prevention
Preventing snake encounters requires awareness, particularly in areas known for rattlesnakes, such as rocky outcroppings, grasslands, and trails. When hiking, stay on designated trails and pay attention to where hands and feet are placed, avoiding reaching into unseen areas like rock crevices or dense brush. Wearing sturdy, high-top hiking boots can offer some protection for feet and ankles. Avoiding headphones can also help ensure you hear a snake’s warning rattle.
If a snake is encountered, give it space. Snakes are not aggressive and strike only when threatened or provoked. If a rattlesnake is heard or seen, freeze in place to locate it, then slowly move away, maintaining a distance of at least five feet. Never attempt to handle, provoke, or kill a snake, as this increases the risk of being bitten.
Emergency Response to a Snakebite
Immediate medical attention is crucial for a snakebite. The first step is to remain calm and call 911 or your local emergency number. While waiting for help, move away from the snake to a safe location. Keep the bitten area still and positioned at or slightly below heart level to help slow the spread of venom.
Remove any jewelry, watches, or tight clothing from the bitten limb before swelling begins. Gently clean the bite wound with soap and water, then cover it with a clean, dry dressing. Do not attempt to cut the wound, apply a tourniquet, suck out the venom, or apply ice, as these actions can worsen the outcome. Rapid transport to a hospital is necessary, as antivenom is the most effective treatment for venomous snakebites.