Are There Rattlesnakes in Colorado?
Yes, two species of rattlesnakes live in Colorado. The western diamondback rattlesnake is found in the western and southwestern regions, while the prairie rattlesnake inhabits the eastern plains and some mountain valleys. Bites are rare and highly treatable. Colorado residents can safely enjoy outdoor activities by knowing where snakes live and taking basic precautions.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated July 22, 2026.
Eastern Diamondback Rattlesnake · Scott Allen Davis CC BY
Panamint Rattlesnake · Matt Berger CC BY
Red Diamond Rattlesnake · Amy Huie CC BY
- 2
- species recorded
- 4,232
- GBIF records
- July, June, August
- peak months
Yes, rattlesnakes are in Colorado. Next you'll want:
Verified species, source iNaturalist
2 types of rattlesnakes recorded in Colorado
2 rattlesnake species have a verified observation record in Colorado, each with at least 10 confirmed sightings. The full list, ranked by how often each is recorded, is below.
- No openly licensed photo yet1
- No openly licensed photo yet2
Counts from verified iNaturalist observations.
Real sighting data, source iNaturalist
3,301 verified observations on iNaturalist of rattlesnake have been recorded in Colorado, most often in July, June, August.
When rattlesnake are recorded in Colorado
Yes, two species of rattlesnakes live in Colorado. The western diamondback rattlesnake is found in the western and southwestern regions, while the prairie rattlesnake inhabits the eastern plains and some mountain valleys. Bites are rare and highly treatable. Colorado residents can safely enjoy outdoor activities by knowing where snakes live and taking basic precautions.
Are they in Colorado?
Yes, two species of rattlesnakes are established in Colorado. The western diamondback rattlesnake is found throughout the western, southwestern, and southern portions of Colorado, particularly in arid and semi-arid regions, canyons, and foothills. The Colorado River drainage, the San Juan Mountains, and surrounding areas provide suitable habitat. The prairie rattlesnake inhabits the eastern plains of Colorado and also occurs in some western and mountain valleys. Both species have lived in Colorado for thousands of years and remain present in appropriate habitat. The western diamondback population has remained relatively stable, while prairie rattlesnakes are still commonly encountered in their range. Despite their presence, encounters with people remain uncommon because rattlesnakes prefer undisturbed wild areas and avoid human activity. Colorado's high elevations in the central and northern mountains provide little suitable habitat for rattlesnakes because cold winters and high altitude are unsuitable for these reptiles. Most Colorado skiing and mountain recreation occurs well above snake habitat. Most Coloradans, particularly those in northern regions and mountains, rarely or never encounter a wild rattlesnake. For more on rattlesnake in Colorado, see ourColorado rattlesnake guide.
How dangerous is it?
A rattlesnake bite in Colorado is a serious medical emergency requiring immediate care, but deaths are very rare. Colorado averages just a few confirmed snake bites per year, with almost no deaths recorded in recent decades. Both Colorado rattlesnake species have hemotoxic venom that affects tissue and blood. Western diamondbacks have more potent venom than prairie rattlesnakes. A bite typically causes pain, swelling, and discoloration at the site within minutes. Untreated bites can lead to tissue damage, loss of limb function, or in rare cases, systemic effects. However, many bites are dry bites with little or no venom injected. The severity of a bite depends on the amount of venom injected, location of the bite, the victim's age and health status, and how quickly medical care is received. Colorado has good access to medical facilities, and hospitals are experienced with snake bites. Antivenom is available at major medical centers. Children face higher risk of serious complications because of their smaller body size. In healthy adults who receive prompt medical care, outcomes are typically very good. You can also browseColorado wildlife.
How to recognize one
Colorado's two rattlesnake species are distinctive and identifiable. The western diamondback is a stocky, thick-bodied snake typically two to five feet long, with a diamond or hexagonal pattern of dark shapes on a lighter background. It has a dark stripe running from the eye toward the jaw and a thick tail with dark and light bands and a prominent segmented rattle. The prairie rattlesnake is usually smaller, typically two to four feet long, with a more tan or brownish coloration and darker blotches or bands along the back. The prairie rattlesnake also has the characteristic segmented rattle at the tail tip. Both species have somewhat triangular heads thicker at the base and both have heat-sensing pits along the upper lip that help them detect warm prey. The segmented rattle is the most distinctive feature of any rattlesnake and is your clearest warning sign. This rattle produces a distinctive buzzing sound when the snake vibrates its tail rapidly. If you hear a buzzing sound while hiking or working outdoors, stop immediately and back away slowly to give the snake room to leave. See all of ourwildlife guides.
What to do if you are bitten or stung
If bitten by a rattlesnake in Colorado, stay calm. Panic increases your heart rate and accelerates venom circulation. Remain still and immobilize the bitten area to prevent further venom circulation. Remove any rings, bracelets, watches, or tight clothing from the bitten limb because swelling will occur within minutes. Call 911 or have someone drive you immediately to the nearest hospital emergency room. Do not attempt to catch or kill the snake. This is general information, not medical advice; if you are bitten, call Poison Control at 1-800-222-1222, or 911 if symptoms are severe. Do not apply ice, tourniquets, or compression wraps unless specifically instructed by emergency personnel. Do not try to cut the bite, suck out venom, apply heat, or use home remedies. Do not give any medications at home. Hospital staff will examine the bite, perform blood work to assess venom effects, monitor your vital signs, and administer antivenom if clinically necessary. Colorado hospitals are equipped with antivenom and experienced staff. OurColorado wildlife guidecovers more species you may run into.
How to prevent encounters
Prevention is effective and straightforward in Colorado. Wear sturdy, closed-toe boots and long pants when hiking or working outdoors in areas where rattlesnakes might be present, particularly in western and southwestern Colorado during warm months. Stay on established trails rather than pushing through grass or brush. Watch carefully where you place your hands and feet, especially around rocks, logs, and fallen wood. Never put your hand into a space you cannot see clearly. Use a tool or stick before moving objects in wild areas. In your yard or around your property, keep grass short and remove wood piles, rock piles, brush, and leaf litter where snakes might hide or rest. Seal gaps under decks, sheds, and porches. Remove rodent sources like unsecured garbage and pet food. Do not leave water dishes outside. Make noise while hiking so snakes can detect you and move away. Avoid hiking at dawn, dusk, or night when snakes may be most active. Check your shoes and gear before putting them on. Shake out sleeping bags before using them when camping.
Where in Colorado and when
Rattlesnakes in Colorado are found primarily in lower-elevation regions. The western diamondback occurs throughout the western, southwestern, and southern portions of Colorado, particularly along the Colorado River drainage, in canyons, foothills, and arid valleys. The San Juan Mountains and surrounding semi-arid regions provide suitable habitat. The prairie rattlesnake inhabits the eastern plains and high plains of Colorado, from the Oklahoma and New Mexico borders northward into the northern plains. They also occur in some western and mountain valleys at moderate elevations where conditions are suitable. Both species are active during warm months, typically from April or May through September or October, with peak activity in spring and early fall when temperatures are moderate. During hot summer middays, they rest in shade or underground. In winter, they enter a dormant state in deep shelters. Most snake encounters and bites in Colorado occur from May through August when people are outdoors and snakes are active. High mountain areas above eight thousand feet have little to no rattlesnake presence.
Harmless lookalikes
Several completely harmless snakes in Colorado are sometimes mistaken for rattlesnakes. The gopher snake is thick-bodied and patterned with blotches, and some people mistake it for a rattlesnake, but it has no rattle and a different head shape. It hisses loudly when threatened, which some people confuse with a rattle. The bullsnake is similar and equally harmless. The king snake is thick-bodied but solid colored or banded, without resemblance to a rattlesnake and without a rattle. Rat snakes, including the prairie kingsnake, are slender and may have patterns but lack the thick body and rattle. Garter snakes are small and striped, entirely different in appearance from rattlesnakes. Bull snakes and other colubrids in Colorado are nonvenomous and help control rodent populations. The most reliable way to distinguish a rattlesnake from these harmless species is the presence of a segmented rattle on the tail. No other Colorado snake has this distinctive feature. If there is no rattle visible or heard, the snake is not a rattlesnake and poses no danger.
Frequently Asked Questions
How many people are bitten by rattlesnakes in Colorado each year? Colorado reports only a few confirmed snake bites annually, with almost no deaths. Bites are exceptionally rare given the state's outdoor recreation. What kind of rattlesnakes are in Colorado? The western diamondback and prairie rattlesnake are the two species in Colorado, each occupying different habitat zones and regions. If I see a rattlesnake while hiking, what should I do? Stop, back away slowly, and give the snake room to move away. Do not approach, corner, or attempt to handle it. If the snake blocks your path, take an alternate route or wait for it to leave. How can I avoid getting bitten? Wear sturdy boots and long pants, stay on trails, watch where you step, make noise while hiking, and avoid hiking at dawn and dusk. Never put your hands into places you cannot see. For detailed information, checkRattlesnake in Coloradoor visitColorado wildlifefor more about local wildlife.
Plan your trip
Best time to see rattlesnake in Colorado: July, June, August
See the month-by-month sighting calendar.
Plan your rattlesnake sighting in Colorado
4,232 verified rattlesnake records have been logged in Colorado, most recently in 2026. See the GBIF records.
Where to look in Colorado
- Bent's Old Fort National Historic Site · Wildlife Watching, Birdwatching · Find hotels
- Black Canyon Of The Gunnison National Park · Wildlife Watching, Birdwatching · Find hotels
- Colorado National Monument · Wildlife Watching · Find hotels
- Curecanti National Recreation Area · Wildlife Watching, Birdwatching · Find hotels
- Dinosaur National Monument · Wildlife Watching, Birdwatching · Find hotels
- Great Sand Dunes National Park & Preserve · Wildlife Watching, Birdwatching · Find hotels
Frequently asked questions
Are they in Colorado?+
Yes, two species of rattlesnakes are established in Colorado. The western diamondback rattlesnake is found throughout the western, southwestern, and southern portions of Colorado, particularly in arid and semi-arid regions, canyons, and foothills. The Colorado River drainage, the San Juan Mountains, and surrounding areas provide suitable habitat. The prairie rattlesnake inhabits the eastern plains of Colorado and also occurs in some western and mountain valleys. Both species have lived in Colorado for thousands of years and remain present in appropriate habitat. The western diamondback population has remained relatively stable, while prairie rattlesnakes are still commonly encountered in their range. Despite their presence, encounters with people remain uncommon because rattlesnakes prefer undisturbed wild areas and avoid human activity. Colorado's high elevations in the central and northern mountains provide little suitable habitat for rattlesnakes because cold winters and high altitude are unsuitable for these reptiles. Most Colorado skiing and mountain recreation occurs well above snake habitat. Most Coloradans, particularly those in northern regions and mountains, rarely or never encounter a wild rattlesnake. For more on rattlesnake in Colorado, see ourColorado rattlesnake guide.
How dangerous is it?+
A rattlesnake bite in Colorado is a serious medical emergency requiring immediate care, but deaths are very rare. Colorado averages just a few confirmed snake bites per year, with almost no deaths recorded in recent decades. Both Colorado rattlesnake species have hemotoxic venom that affects tissue and blood. Western diamondbacks have more potent venom than prairie rattlesnakes. A bite typically causes pain, swelling, and discoloration at the site within minutes. Untreated bites can lead to tissue damage, loss of limb function, or in rare cases, systemic effects. However, many bites are dry bites with little or no venom injected. The severity of a bite depends on the amount of venom injected, location of the bite, the victim's age and health status, and how quickly medical care is received. Colorado has good access to medical facilities, and hospitals are experienced with snake bites. Antivenom is available at major medical centers. Children face higher risk of serious complications because of their smaller body size. In healthy adults who receive prompt medical care, outcomes are typically very good. You can also browseColorado wildlife.
More wildlife in Colorado