See text A pika (/ˈpaɪkə/ PY-kə,[3] or /ˈpiːkə/ PEE-kə)[4] is a small, mountain-dwelling mammal native to Asia and North America.

Another species, the Sardinian pika, belonging to the separate genus Prolagus, has become extinct within the last 2,000 years owing to human activity.

Pikas prefer rocky slopes and graze on a range of plants, primarily grasses, flowers, and young stems.

In the autumn, they pull hay, soft twigs, and other stores of food under rocks to eat during the long, cold winter.

The two species found in North America are the American pika, found primarily in the mountains of the western United States and far southwestern Canada, and the collared pika of northern British Columbia, the Yukon, western Northwest Territories and Alaska.

Most species live on rocky mountainsides, where numerous crevices are available for their shelter, although some pikas also construct crude burrows.

These animals are herbivores and feed on a wide variety of plant matter, including forbs, grasses, sedges, shrub twigs, moss and lichens.

Collared pikas have been known to store dead birds in their burrows for food during winter and eat the feces of other animals.

Pikas do not hibernate and remain active throughout the winter by traveling in tunnels under rocks and snow and eating dried plants that they have stored.

[18] Rather than hibernate during winter, pikas forage for grasses and other forms of plant matter and stash these findings in protected dens in a process called "haying".

[20] Eurasian pikas commonly live in family groups and share duties of gathering food and keeping watch.

North American pikas (O. princeps and O. collaris) are asocial, leading solitary lives outside the breeding season.

[21] The calls are used for individual recognition, predator warning signals, territory defense, or as a way to attract potential mates.

[26] The range of Ochotona was larger in the past, with both extinct and extant species inhabiting Western Europe and Eastern North America, areas that are currently free of pikas.

Pleistocene fossils of the extant steppe pika O. pusilla currently native to Asia have been found also in many countries of Europe from the United Kingdom to Russia and from Italy to Poland, and the Asiatic extant northern pika O. hyperborea in one location in the middle Pleistocene United States.

[1][37] The earliest one is Desmatolagus (middle Eocene to Miocene, 42.5–14.8 Ma[1]), usually included in the Ochotonidae, sometimes in Leporidae or in neither ochotonid nor leporid stem-lagomorphs.

Replacement of large areas of forests by open grassland first started probably in North America and is called sometimes "nature's green revolution".