where are brown bears found in the us
Brown bear The brown bear has lost 98% of its habitat in the lower 48 states. About 95% of the brown bear population in the United States is in Alaska, though in the lower 48 states, they are repopulating gradually but steadily along the Rockies and the western Great Plains.[144][145] The Alaskan population is estimated at 32,000 individuals.[146] The largest populations of brown bears in the lower 48 states are found in the 23,300-km2 Greater Yellowstone Ecosystem and the 24,800-km2 Northern Continental Divide Ecosystem.[147] The Greater Yellowstone Ecosystem of northwest Wyoming is estimated to hold about 674–839 grizzly bears, followed slightly the Northern Continental Divide Ecosystem of northwest Montana with about 765 animals, the Cabinet-Yaak Ecosystem of northwest Montana and northeast Idaho with about 42-65 bears of the species, the Selkirk Ecosystem of northeast Washington and northwest Idaho with only about 40–50 animals and even less the North Cascades Ecosystem of northcentral Washington with about 5–10 grizzlies.[148][149][150][151] These five ecosystems combine for a total of a maximum 1,729 wild grizzlies still persisting in the contiguous United States. Unfortunately, these populations are isolated from each other, inhibiting any genetic flow between ecosystems and creating low genetic diversity in remaining populations which can have negative long-time effects.[147][152] This isolation poses one of the greatest threats to the future survival of the grizzly bear in the contiguous United States.[147] Although there is no record of their existence in the United States east of the Rocky Mountain and Great Plain regions in human history, fossil records from Kentucky and the Ungava Peninsula do in fact show that grizzly bears once roamed in eastern North America.[153]
Red fox Red foxes colonised the North American continent in two waves: during or before the Illinoian glaciation, and during the Wisconsinan glaciation.[17] Gene mapping demonstrates that red foxes in North America have been isolated from their Old World counterparts for over 400,000 years, thus raising the possibility that speciation has occurred, and that the previous binomial name of Vulpes fulva may be valid.[18] In the far north, red fox fossils have been found in Sangamonian deposits in the Fairbanks District and Medicine Hat. Fossils dating from the Wisconsian are present in 25 sites in Arkansas, California, Colorado, Idaho, Missouri, New Mexico, Tennessee, Texas, Virginia, and Wyoming. Although they ranged far south during the Wisconsinan, the onset of warm conditions shrank their range toward the north, and have only recently reclaimed their former American ranges because of human-induced environmental changes.[5] Genetic testing indicates two distinct red fox refugia exist in North America, which have been separated since the Wisconsinan. The northern (or boreal) refugium occurs in Alaska and western Canada, and consists of the large subspecies V. v. alascensis, V. v. abietorum, V. v. regalis, and V. v. rubricosa. The southern (or montane) refugium occurs in the subalpine parklands and alpine meadows of the Rocky Mountains, the Cascade Range, and Sierra Nevada. It encompasses the subspecies V. v. macroura, V. v. cascadensis, and V. v. necator. The latter clade has been separated from all other red fox populations since the last glacial maximum, and may possess unique ecological or physiological adaptations.[17]