Some travelers may feel a little uneasy about the idea of encountering a snake on their vacation. However, most of the snakes in Colorado are harmless. As a matter of fact, of the nearly 30 species of snakes calling Colorado “home”, only rattlesnakes are venomous.
Regardless of their ability to bite or not, all snakes would prefer to be left alone to enjoy soaking up the warm sunshine rather than worry about what you’re up to. Yet it’s still a good idea to know which of our reptilian neighbors to be wary of so that you can ensure your safety while exploring the wilderness of Colorado.
Despite their somewhat scary looks and “bad” reputation, snakes are more interested in small prey like rodents, insects, frogs, worms, and lizards. Even the ones considered dangerous to humans are more likely to slither away from you if given the chance and typically only strike when feeling threatened or startled.
We list some of the most common snakes found in the Centennial State and give you an idea of when and where to expect to see them. There’s no need to be scared of the prospect of seeing a snake on your Colorado adventures, though. However, it’s always a good idea to keep your eyes peeled for Colorado wildlife.
Poisonous Species – Venomous Snakes in Colorado

As mentioned, the only dangerous species of snakes in Colorado for you to be particularly cautious of are the rattlesnakes.
Rattlesnakes
The good news is that they have distinct features that will help you identify them.
- They have rattles at the end of their tails.
- You may see two upper fangs (in addition to the rest of their teeth).
- They have broad, triangular heads accentuated by their narrow necks.
- Their pupils are vertical and elliptical. (Nonvenomous snakes have round pupils.)
- They have facial pits between the nostrils and eyes.
- Venomous snakes have a single row of scales between the vent and the tips of their tails. (Nonvenomous snakes have two rows of scales.)
Besides knowing how to identify these snakes, it’s also helpful to know what to do when you’re in areas that are known for hosting them. Armed with a little extra knowledge helps you avoid an encounter and handle one appropriately if it does occur.

Here are a few tips to follow for additional safety measures:
Look Ahead – Whether there are signs posted to caution you to be on the lookout for snakes or not, it’s wise to always look several yards in front of you, not just where you’re stepping. Snakes often blend into their environment, so they won’t be easy to spot. However, you can watch for dark, oval patterns on the trail that you’re hiking. Keep in mind that sometimes snakes will be stretched out “sunning”, so be sure to stay alert and pay close attention to your surroundings.
Keep Your Distance – If you do encounter a rattlesnake, give it plenty of room. They don’t have external ears so they are particularly sensitive to vibrations. They will feel your footsteps as you approach, which is when they will become on guard and likely coil up. You can also use a long stick or pole to sweep grassy areas before entering. Avoid jumping over logs, turning over rocks, or putting your hands in rock crevices without first checking carefully for snakes.
By keeping your distance, you minimize a snake’s ability to reach you, regardless of its intentions to strike or not. That’s because a rattler can only strike within half its length. Don’t take any risks, though! It can be hard to see how long a snake is when it is coiled up.
Stay Calm – Quick movements can startle a snake, so if you do see one, it’s best to pause and remind yourself that rattlesnakes aren’t interested in attacking humans. We’re too large for them to eat, so they see us as the danger. The best course of action is to back away from the area the snake is in and either go around or change your route altogether. Give the snake plenty of room and it will leave you alone.
What to Do if Bitten – It’s possible that the bite is dry and non-venomous, as is the case in about 25% of all rattlesnake bites. But don’t take any chances by ignoring a bite! Stay as calm as possible and seek medical attention immediately. Here are some dos and don’ts while awaiting medical treatment.
- Don’t try to suck out the venom. The human mouth is full of bacteria that can cause infection, which would make treatment more complicated.
- Don’t cut the wounded area because that can cause considerable bleeding.
- Don’t raise the affected area above your chest as that will allow the venom to reach your heart more quickly.
- Don’t wash the wound. Venom from your skin may be used to identify the correct anti-venom more easily.
- Do remove any tight clothing or jewelry before swelling begins.
- Do remain as still as possible to minimize your blood flow and slow the circulation of the venom.
- Do let the wound bleed as it may allow some of the venom to be released.
- Do remain as calm as possible to keep your heart rate down and to slow the spread of the venom.
For snake bite symptoms and additional treatments, visit Healthline’s article “Rattlesnake Bite”.
Non-venomous Snakes in Colorado

Now that we’ve covered the ones you should be cautious about, let’s look at some of the other common snakes of Colorado. If you spot a snake that does not have a rattle in its tail, you have nothing to fear. It is still wise and respectful to leave it be, though.
Most snakes are ectothermic, meaning they are cold-blooded and regulate their body temperature using external sources. This makes them avoid extreme temperatures and brings them out to do their hunting in milder conditions. Their forked tongues and heat-sensitive facial pits help them determine what is around them.
So keep all of this in mind when planning your outings, as it could help you avoid times and places that may be more prone to snake visitors.
Western Yellow-Bellied Racer
The Western Yellow-Bellied Racer is found in many of the Western States, including Colorado, Utah, New Mexico, Oregon, and Nevada. Its most recognizable feature is its smooth scales, usually in a blue-grey or brown color with a yellow or cream underside.

It likes to eat birds, eggs, lizards, small mammals, turtles, large insects, and other snakes. You’re most likely to see these snakes in areas with plenty of sunshine such as grasslands, forest openings, meadows, and high in the mountains.
Great Basin Gopher Snake
Found throughout the Western Slope of Colorado, the Great Basin Gopher Snake inhabits a variety of areas from dry sandy spaces to pine woodlands. These snakes are straw-colored or pale brown with a row of large square patches of reddish brown and black on their backs as well as similar small patches on their sides. Their underside is a cream color which also has small blotches.

Its choice of defense is to scare away predators with a violent hissing sound. It may also mimic a rattlesnake by vibrating its tail rapidly. Despite its attempts to seem dangerous, humans have nothing to worry about with this species. They feed on small mammals, lizards, insects, birds, and eggs.
Black neck Garter Snake
These snakes have an olive-gray or dark olive-brown coloring with a yellow or orange stripe on their backs and white stripes on their sides. During the daytime, they hunt for amphibians, frogs, tadpoles, worms, and some types of fish. With a diet like that, you may have guessed that the Blackneck Garter Snake is semi-aquatic and can often be found slithering around ponds and streams.
An interesting fact about this snake is that it can release a foul-smelling odor from its anal glands when handled—all the more reason to leave it alone!

Although they don’t usually use their teeth when they bite, they do have toxins in their saliva. So if you are bitten by one, you could have a mild reaction, but ultimately, Blackneck Garter Snakes are not a menace to humans.
Colorado Bullsnake
As one of the largest and most often seen snakes in Colorado, the Bullsnake can be a daunting snake to come across. However, they are no threat to humans. They are nonvenomous but may still strike if threatened. They have also adapted the scare tactic of vibrating their tail when threatened, much like a rattlesnake, but it’s only for self-protection.

They are usually found in open areas such as grasslands, prairies, and meadows. Adult bullsnakes average 4-6 feet in length and help control the rodent population with their diet of mice, rats, ground squirrels, and rabbits. If you see one of these yellowish-brown snakes, just give it time to get out of your way—it’s not interested in bothering you.
Exploring Colorado’s Nature

Snakes are part of Colorado’s natural environment. They live here and play their part in the ecosystem without any plans to hurt us humans, so there’s no need to be frightened to go outside while you’re visiting this beautiful state. You’re armed with knowledge, you know what to look out for, and you’re aware that nearly all Colorado snakes are harmless. It’s time to enjoy the great outdoors with all of its tracks, trails, mountains, lakes, rivers, and forests!
Be sure to check out other articles on our blog for more tips on where to explore, eat, or stay in Colorado. We hope you have a fantastic visit, (snakes and all)!