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 gray to brown with round ears and no tail, 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°F; therefore, they are most active during cooler parts of the day.
The National Park Service Climate Change Response Program funded a project to address questions regarding the vulnerability of the American pika to future climate change scenarios projected for the western United States. A large team of academic researchers and National Park Service staff are involved in this project, and will be working in these eight National Park Service Units: Crater Lake, Great Sand Dunes, Grand Teton, Lassen Volcanic, Rocky Mountain and Yellowstone national parks, and in Craters of the Moon and Lava Beds National Monuments. More information can be found at the "Pikas in Peril" project website: http://science.nature.nps.gov/im/units/ucbn/monitor/pika.cfm.
Quick Facts about Pikas
- Abundant in Yellowstone
- 7–8.4 in. long, 5.3–6.2 ounces (about the size of a guinea pig)
- Active year-round; darts around on rocks; travels through tunnels under snow
- Breed in spring; two litters per year
- Often heard but not seen; makes a distinct shrill whistle call or a short "mew
- Scent marks by frequently rubbing cheeks on rocks
- Late summer it gathers mouthfuls of vegetation to build "haystacks" for winter food; defends haystacks vigorously
- Haystacks often built in same place year after year; have been known to become three feet in diameter
- Like rabbits and hares, pika eat their own feces, which allows additional digestion of food