Pikas (Ochonta princeps) are small mammals that live in alpine tundra above 11,000 feet. Though they look like big(ish) hamsters, they are closely related to rabbits. Imagine a rabbit the size of a sweet potato with round ears, and you basically have a pika.
Pikas are one of the most charismatic animals of the Rocky Mountains. For one thing, they're supper cute. No scales, or slime here, just little round puffballs.
Unlike many small mammals that live in the mountains, Pikas don't hibernate in the winter, but rather stay active all year, even if 9 months of that time is below the snow. Since they are awake all winter, they need to stockpile food. Pikas eat tundra vegetation; grass, flowers, willows, etc. They spend most of the short summer gathering plants into giant (by pika standards) hay piles. These hay piles can be up to two feet by two feet, but you almost never see them as they are under boulders.
The famous wildlife photographer Moose Peterson compared photographing pikas to trying to get a sharp photo of a tennis ball as it's bouncing down your driveway, but sometimes bouncing under the driveway too. Pikas live exclusively on talus slopes since they make their homes under the rocks. As they frantically run back and forth gathering plants for their hay piles, they take similar routes over, under and around boulders, but never seemingly do they take the exact same route twice. They never just walk anywhere. They are either sitting still, usually in the sun, up on top of a rock where they have a good view, or they are running flat out, hell-bent-for-leather. Whenever I go out to photograph pikas, at least 3 out of 4 photos that I come back with are just blurry shots of rocks.
Pikas have very little tolerance for heat. Studies have shown that pikas can only survive for about 6 hours in temperatures above 70 degrees. That's not very warm. This, combined with the above mentioned cuteness is making them something of a poster child for global warming. Over the past few decades, their range in Colorado has already shrunk. As average temperatures increase, they are forced to go higher and higher up the peaks. The problem is that the highest peaks in Colorado are only in the 14,000 foot range, and eventually the pikas run out of mountain. When pikas go locally extinct on any given mountain, it's not some big dramatic event. It's not like you see lots of dead pikas laying around. Rather, one year, there just aren't any pikas chirping and bouncing around where they used to be in the past.