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A pika (/ˈpkə/ PY-kə; archaically spelled pica) is a small, mountain-dwelling mammal found in Asia and North America. With short limbs, very round body, an even coat of fur, and no external tail, they resemble their close relative, the rabbit, but with short, rounded ears.[3] The large-eared pika of the Himalayas and nearby mountains is found at heights of more than 6,000 m (20,000 ft), among the highest of any mammal.

Pikas prefer rocky slopes and graze on a range of plants, mostly grasses, flowers, and young stems. In the autumn, they pull hay, soft twigs, and other stores of food into their burrows to eat during the long, cold winter.[4] The pika is also known as the "whistling hare" for its high-pitched alarm call when diving into its burrow.

The name "pika" appears to be derived from the Tungus piika,[5] and the scientific name Ochotona is from the Mongolian word ogdoi, which means pika.[6] It is used for any member of the Ochotonidae,[7] a family within the order of lagomorphs which includes the Leporidae (rabbits and hares). Only one genus, Ochotona,[7] is recognised within the family, covering 37 species.

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.

Habitat

Collared pika on Hatcher Pass, Alaska

Pikas are native to cold climates, mostly in Asia, North America, and parts of Eastern Europe. Most species live on rocky mountainsides, where numerous crevices are available for their shelter, although some pikas also construct crude burrows. A few burrowing species are native to open steppe land. In the mountains of Eurasia, pikas often share their burrows with snowfinches, which build their nests there.[8] Pikas require cold temperatures to live, and can die if exposed to

A pika (/ˈpkə/ PY-kə; archaically spelled pica) is a small, mountain-dwelling mammal found in Asia and North America. With short limbs, very round body, an even coat of fur, and no external tail, they resemble their close relative, the rabbit, but with short, rounded ears.[3] The large-eared pika of the Himalayas and nearby mountains is found at heights of more than 6,000 m (20,000 ft), among the highest of any mammal.

Pikas prefer rocky slopes and graze on a r

Pikas prefer rocky slopes and graze on a range of plants, mostly grasses, flowers, and young stems. In the autumn, they pull hay, soft twigs, and other stores of food into their burrows to eat during the long, cold winter.[4] The pika is also known as the "whistling hare" for its high-pitched alarm call when diving into its burrow.

The name "pika" appears to be derived from the Tungus piika,[5] and the scientific name Ochotona is from the Mongolian word ogdoi, which means pika.[6] It is used for any member of the Ochotonidae,[7] a family within the order of lagomorphs which includes the Leporidae (rabbits and hares). Only one genus, Ochotona,[7] is recognised within the family, covering 37 species.

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.

Pikas are native to cold climates, mostly in Asia, North America, and parts of Eastern Europe. Most species live on rocky mountainsides, where numerous crevices are available for their shelter, although some pikas also construct crude burrows. A few burrowing species are native to open steppe land. In the mountains of Eurasia, pikas often share their burrows with snowfinches, which build their nests there.[8] Pikas require cold temperatures to live, and can die if exposed to temperatures above 25.5 °C (77.9 °F).[9] Changing temperatures have forced some pika populations to restrict their ranges to even higher elevations.[10]

Characteristics

Ochotona sp. fossils

Pikas are small mammals, with short limbs and rounded ears. They are about 15 to 23 cm (6 to 9 in) in body length and weigh between 120 and 350 g (4 and 12 12 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.[11]

These animals are herbivores, and feed on a wide variety of plant matter, including forbs, grasses, sedges, shrub twigs, moss, and lichens. As with other lagomorphs, pikas have gnawing incisors and no canines, although they have fewer molars than rabbits; they have a dental formula of: 2.0.3.21.0.2.3

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 between 25 and 30 days.[8]

Activity

Pikas have distinct calls that vary in duration. The call can either be short and quick, a little longer and more drawn out, or long songs. The short calls are an example of geographic variation. The pikas determine the appropriate time to make short calls by listening for cues for sound localization.[12] The calls are used for individual recognition, predator warning signals, territory defense, or as a way to attract the opposite sex.[13] There are also different calls depending on the season. In the spring, the songs become more frequent during the breeding season. In late summer, the vocalizations become short calls. Through various studies, the acoustic characteristics of the vocalizations can be a useful taxonomic tool.[14]

Lifespan

The average lifespan of pikas in the wild is roughly seven years. A pika's age may be determined by the number of adhesion lines on the periosteal bone on the lower jaw. The lifespan does not differ between the sexes.[15]

Species

The 37 species described are:

  • Order Lagomorpha[2]
    • Family Ochotonidae: pikas
      • Genus Ochotona
        • Subgenus Pika: northern pikas
        • Subgenus Ochotona: shrub-steppe pikas
          • O. princeps and O. collaris) are asocial, leading solitary lives outside the breeding season.

            Pikas have distinct calls that vary in duration. The call can either be short and quick, a little longer and more drawn out, or long songs. The short calls are an example of geographic variation. The pikas determine the appropriate time to make short calls by listening for cues for sound localization.[12] The calls are used for individual recognition, predator warning signals, territory defense, or as a way to attract the opposite sex.[13] There are also different calls depending on the season. In the spring, the songs become more frequent during the breeding season. In late summer, the vocalizations become short calls. Through various studies, the acoustic characteristics of the vocalizations can be a useful taxonomic tool.[14]

            Lifespan

            The average lifespan of pikas in the wild is roughly seven years. A pika's age may be determined by the number of adhesion lines on the periosteal bone on the lower jaw. The lifespan does not differ between the sexes.[15]

            Species

            The 37 species described are:

            • Order Lagomorpha[2]
              • Family Ochotonidae: pikas
                • Genus Ochotona
                  • Subgenus Pika: northern pikasMany fossil forms of Ochotona are described in the literature, from the Miocene epoch to the early Holocene (extinct species) and present (16.4-0 Ma[1]). They lived in Europe, Asia, and North America.Some species listed below are common for Eurasia and North America (O. gromovi, O. tologoica, O. zazhigini, and probably O. whartoni).

                    • Eurasia
                      • large forms
                        • Ochotona chowmincheni (China: Baode area, late Miocene)[1][16][17]
                        • Ochotona gromovi (Asia, Pliocene, see also North America)[17]
                        • Ochotona gudrunae (China: Shanxi, early Pleistocene)[1][16][17]
                        • Ochotona guizhongensis (Tibet, late Miocene)[1][17][18]
                        • Ochotona lagreli (China: Inner Mongolia, late Miocene to late Pliocene)[1][16][17][18]
                        • Ochotona magna (China, early Pleistocene)[1][17][19]
                        • Ochotona tologoica (Transbaikalia, Pliocene, see also North America)[1][17][19]
                        • cf. antiqua, O. cf. cansus, O. cf. daurica, O. cf. eximia, O. cf. gromovi, O. cf. intermedia, O. cf. koslowi, O. cf. lagrelii, O. cf. nihewanica). The statuses of Ochotona (Proochotona) kirgisica and O. spelaeus are uncertain.[1]

                          The "pusilla" group of pikas is characterized by archaic (plesiomorphic) cheek teeth and small size.[21]

                          The North American species migrated from Eurasia. They invaded the New World twice:

                          • O. spanglei during the latest Miocene or early Pliocene, followed by a roughly three-million-year-long gap in the known North American pikas record[17]
                          • O. whartoni (giant pika) and small pikas via the Bering Land Bridge during the earliest Pleistocene[17]

                          Ochotona cf. whartoni and small pikas of the O. pusilla group are also known from Siberia. The extant, endemic North American species appeared in the Pleistocene. The North American collared pika (O. collaris) and American pika (O. princeps) have been suggested to have descended from the same ancestor as the steppe pika (O. pusilla).[17]

                          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]

                          Pika Ochotona sp. fossil distribution. Extinct pikas and Ochotona indet. are red, steppe pika O. pusilla blue, northern pika O. hyperborea green, other extant pikas black.[1][27][n 3]
                          Fossil occurrences of leporids and ochotonids and global environmental change (climate change, C3/C4 plants distribution)[1]

                          Other genera of ochotonids (currently living only Ochotonidae) include except Ochotona (pika) extinct †Albertona, †Alloptox, †Amphilagus, †Australagomys, †Austrolagomys, †Bellatona, †Bellatonoides, †Bohlinotona, †Cuyamalagus, †Desmatolagus, †Eurolagus, †Gripholagomys, †Gymnesicolagus, †Hesperolagomys, †Heterolagus, †Kenyalagomys, †Lagopsis, †Marcuinomys, †Ochotonoides, †Ochotonoma, †Oklahomalagus, †Oreolagus, †Paludotona, †Piezodus, †Plicalagus, †Pliolagomys, †Prolagus, †Proochotona (syn. Ochotona), †Pseudobellatona, †Ptychoprolagus, †Russellagus, †Sinolagomys and †Titanomys.[1] 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.[28]

                          Ochotonids appeared in Asia between the late Eocene and the early Oligocene, and continued to develop along with increased distribution of C3 grasses in previously forest dominated areas under the "climatic optimum" from the late Oligocene to middle Miocene. They thrived in Eurasia, North America, and even Africa. The peak of their diversity occurred during the period from the early Miocene to middle Miocene, most of them became extinct during the transition from the Miocene to Pliocene, what was accompanied by diversity increase in the leporids. It has been proposed that this switch between ochotonids and larger leporids was caused by expansion of C4 plants (particularly the Poaceae) related to global cooling in the late Miocene, since extant pikas reveal a strong preference for C3 plants (Asteraceae, Rosaceae,and Fabaceae, many of them C3). Replacement of large areas of forests by open grassland first started probably in North America and is called sometimes "nature's green revolution".[1]

                          Notes

                          1. ^ Ochotona spanglei in the Paleobiology Database.[24][pdb 1][pdb 2][pdb 3]
                          2. ^ Ochotona whartoni in the Paleobiology Database.[26][pdb 4][pdb 5][pdb 6][pdb 7][pdb 8][pdb 9][pdb 10]
                          3. ^ The coordinates of additional fossils not listed in the xls file attached to Ge and all paper[1] were taken from the Paleobiology Database.[27][pdb 11][pdb 12][pdb 13][pdb 14][pdb 15][pdb 16][pdb 17][pdb 18][pdb 19][pdb 20][pdb 6][pdb 7][pdb 21][pdb 22][pdb 5][pdb 23][pdb 24][pdb 25][pdb 26][pdb 27][pdb 28][pdb 29][pdb 30]

                          References

                          1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be bf bg bh bi Ge, Deyan; Wen, Zhixin; Xia, Lin; Zhang, Zhaoqun; Erbajeva, Margarita; Huang, Chengming; Yang, Qisen (April 3, 2013). "Evolutionary History of Lagomorphs in Response to Global Environmental Change". PLOS ONE. 8 (4:e59668): e59668. Bibcode:2013PLoSO...859668G. doi:10.1371/journal.pone.0059668. PMC 3616043. PMID 23573205.