Distant relatives of the better-known but enigmatic Japanese "Snow Monkeys", North American Mountain Monkeys can be found in the greater Rocky Mountain region. They construct small, functional lairs and are often found hurtling down steep slopes at high speeds in all seasons. They are gentle at heart but can be dangerous if crossed -- approach them carefully while maintaining eye contact. Offerings of food and drink can't hurt either.
That dude's such a mountain monkey, he hasn't changed his long johns all season!