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The 30 Snakes in Colorado (3 are Venomous)

Written by John Alois
Updated: December 11, 2022
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Colorado is a popular tourist destination in the central United States. It is home to a wide range of environments, from forests to deserts to snowy mountain peaks. So naturally, the large size and habitat variety of the Centennial State allows many kinds of animals to thrive. 

This also means that a variety of snakes inhabit the state as well. This shouldn’t be surprising; while we may think of mountains when we think of Colorado, much of the state is covered in desert and shrubland. Additionally, the American Midwest is famous for its rattlesnakes.

There’s no need to panic, however. Even though Colorado is home to approximately 30 species of snake, only 3 of them are venomous. They are also easy to identify and avoid, since they’re not nearly as aggressive as some stories would have you believe. 

With this list, we hope to put some of Colorado’s most notable snakes on display for the world to appreciate, as well as list tips on how to avoid a venomous snakebite in the wild areas of the state. If you’re at all interested in snakes or Colorado wildlife, read on!

6 Snakes in Colorado

Yellow-Bellied Racer

Yellow-bellied Racer

©Matt Jeppson/

The yellow-bellied racer is one of Colorado’s most common states. You may see it in most grassland, meadow, and even mountain environments, especially those with some water and lots of sunshine. They are easy to identify, with blue-gray or brown bodies with a signature yellow belly that earns it its name. It has a wide range of prey, including small mammals, birds and their eggs, insects, lizards, frogs, turtles, and even other snakes.

Yellow-bellied racers are nonvenomous snakes, so if you see one in the wild, you have nothing to worry about. That being said, despite being legal to own, it still makes a poor pet because of its wild nature; it will never get used to handling. As a racer snake, this species is known for its speed and agility, so taking it out of its tank would be asking for it to get lost in the house! 

However, some yellow-bellied racers have been known to reach 55 inches in length, which means that you would need a big tank for it. This species may be a wonderful addition to the Colorado wilds, but let’s leave them there, for everyone’s sake.


The Bullsnake is a common non-poisonous snake in Colorado yards

©Susan Schmitz/

The bullsnake is one of the largest snakes in Colorado, in both length and width. While they typically grow to be 4 to 6 feet, some have been reported to be as large as 90 inches! Luckily, this snake is nonvenomous and even eats some venomous snakes, along with mammals such as mice, rats, and rabbits. So if you don’t want those snakes and rodents around, you’ll probably want a bullsnake in your area!

In the wild, they can be found in open grasslands, prairies, and meadows, hunting for rodents and birds. When people see one of these yellow-brown snakes basking in the sun, they may mistake it for a rattlesnake. Its tendency to wag its tail when threatened doesn’t help matters. 

However, they share one more similarity with rattlesnakes: they aren’t aggressive toward people that aren’t bothering them. Just leave it alone, and it won’t bother you. Even if you are bitten by one, it’s still a nonvenomous snake, so don’t worry too much.

Blackneck Garter Snake

Blackneck Garter Snake

©Creeping Things/

Colorado is home to four different species of garter snake, all of which are harmless to humans. The common garter snakes of Colorado have red markings on their sides, which this snake doesn’t always have. In this state, the common garter is not the most common garter; that title goes to the western terrestrial garter. We also have the plains garter, which is identified by its yellow-orange stripe and likes to live near water.

However, we find the blackneck garter snake to be the most interesting of the four. In the United States, you can only find this snake in the southwest, and Colorado is about as far north as you’re likely to find them. This subspecies is recognizable among garters for the black stripe along its collar, as well as its olive coloring and three stripes: one on its back that may be yellow or orange, and two white ones on its sides. 

The blackneck garter is semi-aquatic and swims to catch its prey of small fish, lizards, and tadpoles, along with the occasional worm. Though this snake is nonvenomous to humans, picking one up is still a bad idea since its bite may still trigger a reaction. They do make good pets, but leave the wild ones alone!

Venomous Snakes in Colorado

Prairie Rattlesnake


At 4 feet in length, the prairie rattlesnake is the largest of Colorado’s three rattlesnakes. They are also extremely common and have been sighted in each of the state’s counties except some at the highest elevations. They like to inhabit grasslands and shrublands since they enjoy the cover of plants to hide from predators and sneak up on prey. They are most often sighted in the state’s foothills, eastern grasslands, and the Colorado River. Despite their large size, they prefer to stick to a rodent diet.

Even though these snakes are feared for their deadly venom, they truly aren’t interested in hurting people. Even the mighty prairie rattlesnake isn’t big enough to eat a person. Since they only bite in self-defense, the best way to avoid confrontation is to listen for their rattles and keep an eye open for their brown, dark-spotted bodies. Even if bitten, they’re too small to inject a significant amount of venom, so you should be fine as long as you seek medical treatment immediately.

Massasauga Rattlesnake

Iowa Snakes - Massasauga Rattlesnake


There are two types of massasauga in Colorado: the western massasauga and the desert massasauga. Even though they are similar in most ways, most of the state’s massasaugas are of the western variety. These snakes are far less widespread than the prairie rattlers, residing only in the dry areas of southeastern Colorado. They prefer rocky or sandy environments, sometimes being found in dry grasslands.

These snakes are smaller than the prairie rattlesnake, which is already too small to kill the vast majority of people it bites. As such, a massasauga bite is even less deadly, though it should still be taken seriously. However, at only 2 or 3 feet, it will be harder to spot, especially since its brown coloring blends in perfectly with its dry environment. Still, as long as you listen for its rattle and don’t wantonly provoke it, you should have little to fear.

Midget Faded Rattlesnake

Midget Faded Rattlesnake

©Rusty Dodson/

Even though the midget faded rattlesnake, true to its name, is one of the smallest rattlesnakes in the nation at 20 to 30 inches, it’s still a little bit longer than the massasauga. Like its venomous cousin, its small size and yellow coloring make it hard to spot. However, the two usually won’t be found in the same area, since the midget faded rattlesnake prefers the western side of the state. These skilled climbers enjoy the protection to be found from cliffs and shrubs.

The midget faded rattlesnake is the rarest of Colorado’s three venomous snakes. They have been reported in the fewest counties and are limited to areas around the Green and Colorado Rivers. In fact, they are considered in decline and are protected by the state of Colorado. That being said, if faced with a deadly situation, it is still legal to kill them to defend yourselves or your property. 

However, this should never be necessary since these snakes are no more aggressive or threatening to humans than either of Colorado’s other rattlesnakes. Just watch out for them and don’t harass them for the sake of harassing them, and you’re unlikely to annoy them.

The Snakes Of The Centennial State

The dry environments of Colorado are home to some incredible wildlife, including many snakes that we were unable to cover. It’s easy to focus on the 5 or 6 people that die nationwide from snake bites and apply that fear to all snakes, but you truly have little to worry about. 

Out of the approximate 30 species of snake in the state, only 3 are venomous, and one has a declining population. Also, these rattlesnakes are on the smaller side, and even the large ones can never hope to swallow a human being, so they try to avoid confrontation. On top of that, they are even prey for some of the nonvenomous snakes!
As long as you see these snakes for the wild animals that they are and give them the space they need, we can coexist with these reptiles and allow them to flourish. We hope that, with a proper understanding of Colorado’s snakes, we can learn to appreciate all of its wildlife. So don’t let fear of these snakes stop you from enjoying one of the most adventurous states in the nation; get out there and see what other creatures you can find!

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