The ears are very short, rounded, and approximately as wide as high. The nostrils can be completely closed. The legs are short, the hind limbs scarcely longer than the forelimbs. Pikas have five fingers and toes. The feet are heavily furred beneath.
Females have four or six mammae.
The testes of males are abdominal except during the breeding season, when they descend into skin folds at the base of the penis. O. pallasi and O. rufescens also sometimes utilize burrows in open country but live primarily in rocks and talus. All other species that have been investigated seem to be habitat-specific to talus or piles of broken rock, though some populations are found in moist forest areas, living under tree stumps or fallen logs. The two North American species, O. collaris and O. princeps, show the greatest degree of habitat specificity for talus or broken rock. The home range of individuals of these two species almost always includes an area of talus, where the animal shelters in openings among the rocks, and an adjacent area of vegetation, where the animal forages.