The Denver metropolitan area, despite its urban development, is home to native wildlife, including venomous snakes. Rattlesnakes are present, particularly the Prairie Rattlesnake (Crotalus viridis). This species thrives in the varied habitats surrounding the city, making awareness necessary for residents and visitors who spend time outdoors. The proximity of the city to the Rocky Mountain foothills and expansive open space ensures that encounters are possible, especially as human activity expands into natural territories.
Where Rattlesnakes Are Found Near Denver
The Prairie Rattlesnake population is concentrated in the foothills and plains directly bordering the Denver area, particularly along the Front Range. Their habitat includes plains grassland, semi-desert shrubland, and montane woodland up to approximately 9,500 feet in elevation. Specific areas of high activity include open space parks along the C-470 corridor, such as North Table Mountain and Green Mountain Parks.
These reptiles are often found near rocky outcroppings, under logs, in thick grasses, or utilizing abandoned rodent burrows for shelter. They are ectothermic, relying on external temperatures, and are most active from late spring through early fall (typically April to September). During the hottest summer months, they become more nocturnal, hunting at dusk and dawn. On cooler days, they may be found basking on trails or rocks. Urban encroachment occasionally leads to sightings in residential areas adjacent to open space.
Key Features of the Prairie Rattlesnake
The Prairie Rattlesnake is the most common and largest rattlesnake species in Colorado, often reaching lengths of three to four feet. Their coloration typically ranges from light gray or tan to olive-brown, featuring pronounced dark, rounded blotches often ringed in white. These dark patches become more band-like toward the tail.
A defining feature is the wide, triangular shape of its head, which is noticeably broader than the neck. Like all pit vipers, they possess vertical, elliptical pupils and a heat-sensing pit located between the eye and the nostril. The rattle is a series of interlocking keratin segments at the tip of the tail. Juvenile snakes are born with only a small button and cannot produce the audible warning sound until after their first skin shed.
What to Do During an Encounter
Minimizing the risk of an encounter involves adopting specific preventative measures while recreating in rattlesnake territory.
Prevention
- Always remain on marked trails.
- Wear sturdy, close-toed footwear and long pants for protection.
- Never place hands or feet where you cannot clearly see (e.g., reaching into rock crevices or under logs).
- Keep pets, especially dogs, on a short leash, as their curiosity often leads to investigation of snakes.
If a bite occurs, seek immediate medical attention by calling 911. Remain as calm and still as possible to slow the circulation of venom, keeping the affected limb at or slightly below heart level. Remove any constrictive items like rings or tight clothing from the bitten area before swelling begins. Do not attempt outdated first aid methods such as applying a tourniquet, cutting the wound, sucking out the venom, or applying ice, as these actions are ineffective and can cause further tissue damage.