While trail running this past summer, we almost ran into a moose in the Indian Peaks Wilderness; nearly stepped on a snake at a Boulder trailhead; and glimpsed a bear and her cubs in Steamboat Springs. We got off easy: In 2019, a trail runner near Fort Collins had to kill an attacking mountain lion with his bare hands. Animals aren’t usually spoiling for a tussle, but here are some survival guidelines, just in case.

Mountain Lions

Never approach a cougar, but don’t run, either; you don’t want it to think you’re prey. Rather, act like a threat by speaking in a firm voice and making yourself as large as possible. If a mountain lion does attack, fight back and go for the eyes. These animals don’t like a challenge.

Black Bears

You might have been told to ball up and play dead in the event of a bear encounter. That’s good advice for grizzlies—which have been considered locally extinct since 1951. Like mountain lions, our less aggressive black bears likely won’t square up to a threat, so get big and loud. (Just to be safe, though, avoid known black bear habitats at dawn and dusk; that’s when they are the most lively.)


The only venomous snakes you’ll encounter in Colorado have rattles. Should you hear that heart-stopping shake, back off and give the serpent a wide berth. Even if it’s still, chances are it knows you’re there: Snakes can sense your presence based on your movements and body heat.


Perhaps the most dangerous animal on this list, moose record the most animal-human conflicts in Colorado and get particularly aggressive in summer, after the cows give birth. If you stumble upon protective parents, move away slowly. Should one look like it’s charging, sprint in the other direction and try to put a large object, like a tree or a boulder, between you and the giant ungulate.

Sarah Banks
Sarah Banks
Sarah produces, photographs and researches the photography in the print edition of 5280. In addition, she photographs and writes for 5280.com.
Spencer Campbell
Spencer Campbell
Spencer Campbell writes features and edits service packages.