10 Most Dangerous Animals In Colorado You Need To Be Wary Of

dangerous animals in colorado

Colorado is famous for its vivid landscape of mountains and forests, high plains, deep canyons and desert lands. In these breathtaking North American spaces is an incredible range of wildlife, from the iconic bald eagle to enormous elk and moose. But what about the most dangerous animals in Colorado?

This tremendous state is popular for many activities that venture into the great outdoors. Before hitting the mountainous hiking trails and unwinding amidst nature, be sure to clue up on what deadly creatures and wild animals you may encounter. You never know what you might run into while on your great adventure.

Even though wildlife officers say animal attacks are rare in Colorado, they can still happen, and they do still happen. From black bears to mountain lions, rattlesnakes to venomous spiders, Colorado is not short of dangerous animals.

Colorado Bighorn Sheep

Bighorn Sheep
Photo by Envato Elements
Latin NameOvis canadensis
Where To FindAcross a steep and mountainous habitat, and in National Parks in Colorado.
CharacteristicsLarge sheep, varying in color from light to dark brown with a light white patch on the rump, large curving horns.
IUCN StatusLeast concern

Bighorn sheep can be sighted across the mountain ranges in Colorado. The impressively large, curled horns are a symbol of status and a weapon used in epic battles among herds. Clashing horns can be heard across the mountainous region as males square up to each other, rear up on their hind legs, and propel themselves at each other, some reaching a top speed of 20 mph.

Besides the famous horns, this sheep can also be identified by the light white patch on the rump. The main body can vary in color but is often a mid-brown that blends in with the natural surroundings. These sheep can weigh between 117 to 279 pounds and are as big as adult humans.

If a bighorn feels threatened, they will charge. This is a scenario to avoid, the speed paired with the overall weight and strong horns is not a combination you want to encounter. These large mammals are known for their stubbornness, so it is best to give them plenty of space at all times. The same advice is given regarding mountain goats, another potentially dangerous animal if made to feel threatened.

Black Bear

black bear
Photo by Envato Elements
Latin NameUrsus americanus
Where To FindGambel’s oak and aspen, near open areas of natural fruit sources.
CharacteristicsSmall and rounded ears, typically between 4-6 feet from head to toe.
IUCN StatusLeast concern

Black bears can be found across the USA, all the way from Ohio to Colorado. This is the only bear species found in Colorado, and despite common belief, they do their best to avoid human contact and are not naturally aggressive. Bear attacks are extremely rare in Colorado but not unheard of; a woman was killed in a rare bear attack, just the fourth fatality since records began in 1960.

You should always be respectful of these mammals. They are large beasts and have powerful jaws and big claws. If provoked, a black bear will protect itself and are likely to win the fight.

Colorado’s largest black bear populations live in areas of Gambel’s oak and aspen, near open areas of natural fruit sources. If you do sight a black bear while enjoying Colorado’s great outdoors, avoid getting too close. If you find yourself near to a bear, make plenty of noise and they will move on by themselves.


an Elk
Photo by Envato Elements
Latin NameCervus canadensis
Where To FindAcross the lowlands of Routt National Forest and other areas of Colorado.
CharacteristicsSimilar to deer but bigger, light brown in color with a narrow nose and pointed antlers.
IUCN StatusLeast concern

Colorado’s elk population is the largest in the world; there are over 280,000 animals in the wild. In Fall, visitors often come to Colorado to hear the booming bugle of these magnificent animals during mating season. They also tempt hunters deep into the woods.

Elk are light brown (a bull elk can be almost golden) with a pale yellow rump and weigh between 660 and 780 pounds. They are most commonly seen in the lower elevation areas in the Routt National Forest.

These huge mammals can be extremely dangerous animals. Females tend to be aggressive in the Spring, while males are more aggressive in the Fall season. An unpredictable elk can launch into an attack at any moment, so it’s best to always keep your distance.


a moose
Photo by Envato Elements
Latin NameAlces alces
Where To FindIn higher elevation areas, State Forest State Park near North Park.
CharacteristicsExtremely large mammals, dark in color, with a bell-like nose and broad, flat antlers.
IUCN StatusLeast concern

Moose were reintroduced into Colorado’s ecosystem just over 30 years ago and they are thriving in parts of the state. Because of this, they have few natural enemies. Their biggest threat is humans mistaking them for elk. Elk are a hunted animal in Colorado, whereas moose are not.

How can you tell the difference between moose and elk? Well, moose are far bigger to start with! Moose are dark brown and appear almost black, with a large bulbous nose and fur extending down from the neck.

Just like elk, these animals can be dangerous. Between protecting young and mating season, you certainly don’t want to get in the way of these 1,200 lbs beasts!


Photo by Envato Elements
Latin NameCanis latrans
Where To FindMidwestern prairies and the Front Range of Colorado, but highly adaptable to live in urban areas as well.
CharacteristicsSimilar size to large domesticated dogs, light brown colored fur with a black tip on the tail. Live and hunt in packs.
IUCN StatusLeast concern

Don’t be misled by the small size of a coyote. While they are often wary of humans, they still pose a threat, especially to children or dogs. Coyotes hunt in packs, so always be cautious when out camping in Colorado’s wilderness.

Most coyote attacks on humans can be prevented by simple changes to our behavior. It is important to never feed coyotes. And if encountered, don’t run from them but stand your ground. If you do experience any aggressive behavior from an individual coyote, you should report it to the local rangers as it may be rabid.

Coyotes are native to the Midwestern prairies and the Front Range of Colorado. They are highly adaptable and intelligent animals found in Colorado.

Mountain Lion

Mountain Lion
Photo by Envato Elements
Latin NamePuma concolor
Where To FindFoothills and canyons with adequate cover and ample prey.
CharacteristicsA large and slender big cat, color varies from light grey to reddish-brown, with black markings on each side of the muzzle and on the back of the ears.
IUCN StatusLeast concern

Mountain lions are one of North America’s biggest cats. They are also commonly known as cougar, panther, or puma. In Colorado alone, the population is estimated from 3,000 to 7,000 mountain lions. Summit County is a favored place for mountain lions with the mix of foothills and canyons, this provides adequate cover and ample prey.

Like their African savannah counterparts, mountain lions can be extremely dangerous animals if threatened or provoked. They have powerful jaws and large claws that could prove fatal if the lion attacks.

If you do encounter a mountain lion in Colorado, it is imperative to stay calm. Talk firmly to it and move slowly backward, if you can do so safely. Most of the time lions do their best to avoid contact and rarely attack humans. However, you should be aware of what is around you when hiking through the foothills of Colorado.

Brown Recluse Spider

Brown recluse spider
Photo by Pixabay
Latin NameLoxosceles reclusa
Where To FindIn dark, hidden spaces, like guttering or leaf piles.
CharacteristicsBrown color variations with a violin-shaped marking on their abdomen.
IUCN StatusLeast concern

Brown recluse spiders are a rare sight in Colorado. This species of spider thrives in the more southern states of America, like Arizona, New Mexico, Texas, California, and Nevada. However, they can occasionally be found outside their normal range, being transported accidentally with goods and produce.

A bite from a brown recluse is nasty with venom that causes tissue death. The initial bite can be as mild as a pinprick, with some cases developing into a bluish patch and blistering. The bite can take a couple of months to heal and permanent scarring is highly likely.

Black Widow Spider

black widow spider
Photo by Unsplash
Latin NameLatrodectus mactans
Where To FindNear the ground in dark, undisturbed areas
CharacteristicsBlack coloration with a red hourglass pattern. Smaller than a quarter coin.
IUCN StatusLeast concern

Black widow spiders are far more common in Colorado. These iconic spiders are black with a red hourglass pattern on the abdomen. They often build webs near the ground in dark, undisturbed areas.

A bite from a black widow can cause some of the following side effects:

  • muscle pain
  • nausea
  • mild paralysis of the diaphragm
  • breathing difficulty

While most black widow spider bite victims recover without serious issues, a bite can be deadly to the elderly and to very small children. Urgent medical attention is needed in any case.


tick on a green leaf
Photo by Envato Elements
Latin NameIxodida
Where To FindIn long grassy spaces, domestic dogs and other smaller mammals in the wild.
CharacteristicsBlack or brown in color, teardrop-shaped body.
IUCN StatusLeast concern

Ticks are blood-sucking parasites that can be found across the globe. Believe it or not, these tiny bugs are one of the most dangerous animals in Colorado! The Rocky Mountain wood tick often bites both humans and dogs in spring, becoming dormant with warm weather in summer.

One risk of being bitten by a tick is contracting Colorado tick fever (CTF). Symptoms of this disease include:

  • fever
  • chills
  • headache
  • body aches
  • fatigue

Some rare cases also display a sore throat, vomiting, abdominal pain, or skin rash. How do you avoid getting bitten by a tick? Use strong and effective bug spray (containing DEET) when out hiking or camping, especially in springtime.


a rattlesnake
Photo by Envato Elements
Latin NameCrotalinae
Where To FindAcross the whole of Colorado, especially in the foothills of the mountainous region.
CharacteristicsFamous rattle tail with a large, triangular head, vertical pupils, and a heavy body.
IUCN StatusLeast concern

There are three species of snakes posing a serious threat in the state: the prairie rattler, the massasauga rattler, and the midget faded rattler. In Colorado, rattlesnakes are known as Diamondbacks.

In addition to the obvious rattle end of the snake, Colorado’s rattlesnakes also have a large, triangle-shaped head, vertical pupils, and a thick, heavy body. Rattlesnakes can be found in just about every corner of Colorado, but tend to stick to prairie, lowlands and the foothills of the Rocky Mountain range.

Rattlesnakes generally hide from people, so encounters along popular trails are uncommon. If you do encounter one in the wild, keep yourself to yourself and avoid provoking the snake. As when any wild animal feels threatened, a rattlesnake will attack if pushed and they are highly venomous.

Top Hiking Safety Tips

hiking in Colorado
Photo by Envato Elements

Hiking is one of the most popular activities enjoyed in Colorado. Here are some specific top tips to keep in mind just in case you encounter a wild and dangerous animal during your ramble:

  • Deer – always respect a doe with a fawn, as they will always protect their young; bucks can get aggressive in Fall and will charge at humans.
  • Bears and lions – create lots of noise to make yourself appear bigger.
  • Moose – stay quiet and back away to slowly create distance.
  • Never turn your back on a wild animal.
  • Don’t try to get close to wild animals. This is an unnecessary risk.

Colorado wildlife officers suggest using the Thumb Rule:

  1. Extend your arm in front of you.
  2. Make a thumbs up gesture.
  3. Place your thumb over the animal in point of view.
  4. If you can still see parts of the animal around your thumb, then you’re too close. Back up and give the animal space.

What is the deadliest creature in Colorado?

The state’s majestic mountain lion is often believed to be the most dangerous animal in Colorado. However, with only 22 attacks on humans recorded since 1990, the fear of the mountain lion is probably greater than the risk. Elk are equally as dangerous, if not more so due to the higher rate of encountering them. Elk can be unpredictable and are extremely large animals; when they charge at full speed, they can cause significant harm to anyone caught in the way.

How common are animal attacks in Colorado?

Generally, wildlife attacks on humans in Colorado are rare. That being said, the wilderness does have a diverse ecosystem that has plenty of dangerous animals that could seriously injure or harm humans if provoked. The main thing to remember when out in the Colorado wilderness is to respect nature and give all creatures the space they need.

Are there Panthers in Colorado?

Colorado does have panthers, also known as pumas or mountain lions. This is a wild big cat found in the more mountainous regions of the state. These big cats tend to be aloof and elusive to humans, avoiding popular hiking trails and areas, so encounters are rare.

Are there venomous snakes in Colorado?

Colorado does have three species of venomous snakes: the prairie rattler, the massasauga rattler, and the midget faded rattler. These rattlesnakes, also known as Diamondbacks, can be found across the whole of Colorado and are one of the most dangerous animals you could encounter in the wild.


For more than 11 years, Joe has worked as a freelance travel writer. His writing and explorations have brought him to various locations, including the colonial towns of Mexico, the bustling chowks of Mumbai, and the majestic Southern Alps of New Zealand. When he's not crafting his next epic blog post on the top Greek islands or French ski resorts, he can often be found engaging in his top two hobbies of surfing and hiking.

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