related lineages repopulated Alaska and northern Canada from Eurasia after the Last Glacial Maximum (>25,000 BP).

In the 19th century, the grizzly was classified as 86 distinct species. By 1928 only seven grizzly species remained, and by 1953, only one species remained globally. However, modern genetic testing reveals the grizzly to be a subspecies of the brown bear (Ursus arctos). Biologist R.L. Rausch found that North America has but one species of