Pikas are closely related to rabbits, although smaller than the average rabbit and with shorter ears. There are several species living in mountainous regions of Asia and North America. This is the American pika. It lives in boulder fields at or above the tree line. Spotted at Mount Evans in Colorado.
Nikon D300 with Nikkor 200-400mm lens (at 400mm) ISO 400, f/5 at 1/250th of a second