Giant pika
The giant pika or Wharton's pika ("Ochotona whartoni") is an extinct mammal species in the family Ochotonidae. It lived during the Pleistocene and early Holocene in northern parts of North America (Alaska, US and Canada). Very similar forms have also been found also in Siberia. Distribution. The giant pika has been found in Alaska (United States), Yukon ("O. whartoni" and "O" cf. "whartoni", large number of locations), Alberta and Ontario (Canada). A close relative "O. whartoni" ("O." cf. "whartoni") is also known from Eastern Siberia and Kolyma. The ancestors of these pikas migrated from Eurasia to North  America during the Early Pleistocene via the Bering Land Bridge, along with another group of small pikas close to the ""O. pusilla" group". This migration was separate from that of "O. spanglei", which entered North America approximately three million earlier at the Miocene-Pliocene boundary. Biology. The giant pika is much larger than other North American pikas, but is of a similar size to the extinct early and middle Pleistocene "O. complicidens" and extant "O. koslowi" (Koslov's pika), both from China, and may belong to one of them. Unlike the American pika ("O. princeps"), which inhabits scree slopes, the  giant pika's habitat was largely tundra and steppe, similar to Eurasian pikas. Occurrence and extinction. The giant pika has been found in North America from the Irvingtonian (1.8–0.3 Ma, Lower–Middle Pleistocene) throughout Middle Pleistocene to Late Pleistocene (0.1–0.0Ma) locations. The last occurrence of the giant pika is known from early the Holocene of eastern North America (a cave at Elba in the Niagara Escarpment, Ontario) and its radiometric date is 8670±220 years BP (C age) or 10251-9140 BP (calibrated date). It is possible that it survived in the rocky areas along the Niagara Escarpment as a relict  population.