Pikas are tailless, have somewhat circular ears, are grayish to brown and are about the size of a guinea pig. Their total length is 6.8 to 8.4 inches (170-210 mm), they weigh 5.3 to 6.2 ounces (150-175 grams). Like all lagomorphs, they have double upper incisors but the front pair is large and functional and the very small posterior pair is peg-like. Pikas have hair on their feet, an adaptation that gives them great traction as they scurry about on rocks. Pikas are recognizable behaviorally. They dart about on talus slopes and you may hear their distinct, shrill whistle call or a short “mew” that sounds like an insolent cat. Often the call will give away their presence even though you cannot sight them.
Distributed discontinuously in mountainous areas from southern British Columbia and southern Alberta, south to southern California, Nevada, southern Utah, and northern New Mexico, and east to Wyoming and Colorado. They are typically found in mountains in Idaho, but a population exists in Craters of the Moon National Monument in southern Idaho.
Found from sea level to 9800 feet (3000 m) in northern range, infrequently below 8200 feet (2500 m) in the southern part of their range. Restricted to rocky talus slopes, primarily talus-meadow interface. Often found on high alpine slopes at about 2700 m, above treeline up to limit of vegetation. Also found at lower elevations in rocky areas within forests or near lakes. Occasionally found on mine tailings , or piles of lumber or scrap metal. Ideal habitat includes rockslides that include rocks large enough to allow them freedom of movement under and between rocks and small patches of vegetation for food. Unique habitat in Idaho includes the Craters of the Moon National Monument where the landscape is characterized by rather recent lava flows not typical of mountain talus slopes. It has been reported that a melanistic (black) form of Pikas exists in Craters of the Moon, probably an adaptation to the black rocks.
Feeds primarily on grasses and sedges, but also eats flowering plants and shoots of woody vegetation, even conifer twigs and lichen . They are active food storers and haul in and pile rather large quantities of vegetation in piles up to 3 feet in diameter and holding up to 50 pounds of vegetation. The “food” they cut provides them a good supply of food for the winter.
Active all year. Relatively inactive on warm days; may be inactive at midday in hot weather near lower elevational limit. In late summer and fall, harvests and stores food and defends haypiles built for winter consumption. May forage in winter in snow tunnels. Does not dig burrows, but may enlarge den or nest site under rock. May defend territory of about 400-700 m2; home range is about twice that size, but varies seasonally (largest during spring breeding season). Male and female territories are same average size. Adjacent home ranges tend to be occupied by opposite sexes. Colorado study found population density of 3-10/ha in favorable habitat in mid-August (same as in other regions); density-related social behavior maintains population stability. Juveniles tend to stay on natal or adjacent home range. Individuals may live 5-7 yr; adult mortality is 37-56%/yr. Pikas practice copraphagy . They do not have the enzyme necessary to digest cellulose, a main component of their herbaceous diet. Instead, they have a large caecum, or sac, in their large intestine, where various microorganisms digest the cellulose . Pikas defecate soft pellets that still contain considerable nutrients, especially vitamin B, where are not asorbed in the caecum . The soft pellets, usually deposited at night, are reingested (eaten) and the vitamin B is then absorbed in the small intestine. The final product is small, round, dry fecal pellets, about the size of a BB.
Seasonally polyestrus . Gestation lasts about 30 days. Young are born May-September (possibly March in some low elevation areas). Female produces 1-2 litters of 2-5 young/litter. Young depend on mother for at least 18 days, and are weaned at 3-4 wk. Juveniles establish territories and haypiles, but do not breed until second summer.
|Status:||Protected nongame species|
Important State References:
Bunnell, S.D. and D.R. Johnson. 1974. Physical factors affecting pika density and dispersal. J. Mammal 55:866-869.