Boulder trail wildlife safety

The wildlife is one of the best parts of hiking around Boulder, and it very rarely causes trouble. The animals you're most likely to think about, black bears, mountain lions, prairie rattlesnakes, and moose, all live along the Front Range, but they generally want nothing to do with people. The handful of things that keep encounters safe are the same for almost every animal: keep your distance, never feed or approach wildlife, keep dogs leashed and close, make enough noise that you don't surprise anything, and if you do meet a large animal, stay calm and don't run.

Below is what you might encounter near Boulder and exactly how to respond, animal by animal, following Colorado Parks & Wildlife guidance. None of this is meant to scare you off the trail. It's meant to make the time you spend out there easy and confident.

Black bears

Boulder is black bear country, and that's the only kind of bear here: Colorado has no wild grizzly population, so the bears you might see are shy, and far less aggressive than the grizzlies you'd worry about farther north. They're most active from spring through late fall, and they get very food-focused in late summer and autumn as they fatten up before denning.

What Colorado Parks & Wildlife recommends:

• Make noise as you hike so you don't surprise a bear at close range. Most bad encounters start with a startled animal.
• Never run. Stand your ground, stay calm, and talk in a steady voice so the bear knows you're a person.
• Back away slowly and give the bear a clear escape route. Never get between a bear and its cubs, or between a bear and food.
• Store food and scented items securely, especially when camping. A bear that finds human food learns to come back, and that rarely ends well for the bear.
• Never feed a bear or leave food out to photograph one.

Mountain lions

Mountain lions (also called cougars or pumas) live throughout Boulder's foothills, but they're secretive and mostly active at dawn and dusk, so actually seeing one is uncommon and an attack is extremely rare. Still, it's worth knowing what to do, because the right response is the opposite of what instinct might tell you.

If you encounter a mountain lion, Colorado Parks & Wildlife advises:

• Do not run. Running can trigger a lion's instinct to chase.
• Look as big as you can. Stand tall, raise your arms, open your jacket, and stay facing the lion.
• Keep kids and dogs close. Pick up small children so they don't panic or run, and keep dogs leashed at your side.
• Back away slowly while keeping eye contact, giving the lion space to leave.
• If it's aggressive, get loud and throw things (rocks, sticks, a water bottle). If a lion actually attacks, fight back and protect your head and neck. Do not play dead.

Prairie rattlesnakes

The prairie rattlesnake is the venomous snake you might meet around Boulder, and it favors the warm, lower foothills and grasslands, especially east and north of town. You're most likely to cross paths with one on sunny, open trails like Rabbit Mountain, Marshall Mesa, and Hall Ranch. They're most active in the warmer months and on warm days, often basking where the sun hits.

How to share the trail with them:

• Watch where you step and where you put your hands, especially near rocks, logs, and tall grass at the trail edge.
• Stay on the trail and keep dogs on the trail too. Most surprises happen off-trail in the brush.
• Give a snake room. If you see or hear one, stop, locate it, and go around with plenty of space. A rattle is a warning, not a threat.
• Never handle, poke, or try to kill a snake. Most bites happen when people mess with them. Leave it alone and it will leave you alone.
• Keep dogs leashed on the foothills trails. Curious dogs are the ones that get bitten, usually on the nose.

Moose in the high country

If you head up into the mountains west of Boulder, to Brainard Lake and the Indian Peaks, you're in moose country. Moose look calm, but they're one of the more genuinely dangerous animals in Colorado: they're huge, faster than they look, and they will charge when they feel threatened, especially a cow with a calf. Most people underestimate them because they don't seem like predators.

Around moose, Colorado Parks & Wildlife guidance comes down to distance and dogs:

• Keep well back and never approach one for a photo. Give it a wide, respectful buffer.
• Leash your dog and keep it far from the moose. Dogs look like wolves, a moose's natural predator, and are one of the most common triggers for a charge.
• Read the warning signs. A moose that lays its ears back, raises the hair on its neck, or licks its lips may be about to charge.
• If a moose charges, run and put something solid between you, like a large tree, boulder, or car. Unlike with a lion, running from a moose to reach cover is the right move.

General rules that keep every encounter safe

Most of wildlife safety around Boulder comes down to a few habits that work no matter what you meet:

• Keep your distance. Never approach wildlife, even something that looks calm or used to people. Use a zoom lens or binoculars, not your feet, for a closer look.
• Leash your dog. A dog under control is safer for you, your dog, and the animals. Loose dogs cause a large share of serious encounters. See our guide to hiking with dogs in Boulder for local rules.
• Never feed wildlife, and never leave food or trash behind. A fed animal becomes a bold animal, and often a dead one.
• Make some noise on blind corners and in brush so you don't startle anything at close range.
• Stay alert at dawn and dusk, when many animals move most.
• Don't run from a bear or a lion. Stand tall, stay calm, and back away. (Moose are the exception: from a charging moose, run for cover.)

Once these become second nature, they fade into the background and you can just enjoy the trail. For more on planning a hike here, from parking to altitude to afternoon storms, see our Boulder hiking hub.

Boulder wildlife safety: common questions

Recommended nearby

Sources

The animal-encounter advice on this page follows Colorado Parks & Wildlife's "Living with Wildlife" guidance:

• Colorado Parks & Wildlife: Living with Wildlife
• Colorado Parks & Wildlife: Living with Black Bears
• Colorado Parks & Wildlife: Living with Mountain Lions
• Colorado Parks & Wildlife: Living with Moose

This guide is general trail advice, not emergency instruction. In any wildlife emergency, call 911, and report aggressive animals to Colorado Parks & Wildlife.