Pikas are small mammals, with short limbs and rounded ears. They are about 15 to 23 centimetres (5.9 to 9.1 in) in body length and weigh between 120 and 350 grams (4.2 and 12.3 oz), depending on species. Like rabbits, after eating they initially produce soft green feces, which they eat again to take in further nutrition, before producing the final, solid, fecal pellets. Some pikas, such as the collared pika, have been known to store dead birds in their burrows, for food during winter.
These animals are herbivores, and feed on a wide variety of plant matter, including forbs, grasses, sedges, shrub twigs, moss, and lichen. As with other lagomorphs, pikas have gnawing incisors and no canines, although they have fewer molars than rabbits, giving them a dental formula of: 18.104.22.168.0.2.3
Rock-dwelling pikas have small litters of fewer than five young, while the burrowing species tend to give birth to more young, and to breed more frequently, possibly due to a greater availability of resources in their native habitats. The young are born after a gestation period of between 25 and 30 days.