is not confirmed. There have been five reports of unconfirmed dire wolf fossils north of 42°Nlatitude at Fossil Lake, Oregon (125,000–10,000YBP), American Falls Reservoir, Idaho (125,000–75,000YBP), Salamander Cave, South Dakota (250,000YBP), and four closely grouped sites in northern Nebraska (250,000YBP). This suggests a range restriction on dire wolves due to temperature, prey, or habitat. The major fossil-producing sites for A.d.dirus are located east of the Rocky Mountains and include Friesenhahn Cave, near San Antonio, Texas; Carroll Cave, near Richland, Missouri; and Reddick, Florida. Localities in Mexico where dire wolf remains have been collected include ElCedazo in Aguascalientes, Comondú Municipality in Baja California Sur, ElCedral in San Luis Potosí, ElTajo Quarry near Tequixquiac, state of Mexico, Valsequillo in Puebla, Lago de Chapala in Jalisco, Loltun Cave in Yucatán, Potrecito in Sinaloa, San Josecito Cave near Aramberri in Nuevo León and Térapa in Sonora. The specimens from Térapa were confirmed as A.d.guildayi. The finds at San Josecito Cave and ElCedazo have the greatest number of individuals from a single locality. In South America, dire wolves have been dated younger than 17,000 YBP and have been reported from five localities: Muaco in the western Falcón state of Venezuela, Talara Province in Peru, Monagas state in eastern Venezuela, the Tarija Department in Bolivia, and Ecuador. If the dire wolf originated in North America, the species likely dispersed into South America via the Andean corridor, a proposed pathway for temperate mammals to migrate from Central to South America because of the favorable cool, dry, and open habitats that characterized the region at times. This most likely happened during a glacial period because the pathway then consisted of open, arid regions and savanna, whereas during inter-glacial periods it would have consisted of tropical rain forest. In 2020, a fossil mandible from a dire wolf was found in the vicinity of Harbin, northeastern China. The fossil was taxonomically described and dated 40,000 YBP. This discovery challenges previous theories that the cold temperatures and ice sheets at northern latitudes in North America would be a barrier for dire wolves, which was based on no dire wolf fossils being found above the 42° latitude in North America. It is proposed that the dire wolf followed migrating prey from mid-latitude North America then across Beringia into Eurasia. Extinction During the Quaternary extinction event around 12,700YBP, 90genera of mammals weighing over became extinct. The extinction of the large carnivores and scavengers