Learn more about pika research in the Science Minute Movie: Pikas Living on the Edge

Pikas (Ochotona princeps) are small territorial mammals about the size of guinea pigs. They inhabit rocky alpine and sub-alpine zones feeding on the vegetation that fringes their preferred talus slopes. Colored grey to brown with round ears, they blend in with their rocky home and agilely maneuver between and underneath obstacles. Because pikas do not hibernate, this relative of the rabbit must gather enough plant materials during the short growing season to survive the winter. Piles of drying vegetation, called haystacks, and a distinctive high-pitched call are the most recognizable indicators of active pika habitat. Prolific breeders, pikas usually have two litters of young each summer. The mortality rate is high for the youngsters and the first litter has a greater rate of survival. These small mammals are sensitive to temperatures above 77.9 ºF; therefore, they are most active during cooler parts of the day. While abundant in the Greater Yellowstone Ecosystem, pika numbers are declining in other western regions. Studies suggest changing climate is the probable cause of their overall decline.