Ursus americanus

Cronin et al. (1991) found very similar mtDNA haplotypes among black bears from Alaska, Montana, Oregon, and New Hampshire, though divergent haplotypes were identified in the populations from Montana and Oregon; evidently there has been maintenance of polymorphism and considerable gene flow throughout the history of the species. Bears from insular Newfoundland, New Brunswick, and Quebec, and most individuals from Alberta, exhibited very closely related mtDNA haplotypes; Newfoundland bears apparently arose through rapid genetic drift associated with a founder effect during postglacial colonization (Paetkau and Strobeck 1996).

Bears from Haida Gwaii (Queen Charlotte Islands), Vancouver Island, and coastal mainland British Columbia are indistinguishable with respect to mtDNA, but these bears are highly distinct from inland continental bears; the coastal mtDNA lineage occurs in each of the three recognized coastal subspecies, suggesting that the morphological characteristics differentiating these taxa may be postglacially derived (Byun et al. 1997).

See Cronin et al. (1991) and Shields and Kocher (1991) for information on phylogenetic relationships of North American ursids based on an analysis of mitochondrial DNA (black bear has been separated from brown and polar bears much longer than brown and polar bears have been separated from each other).

Widespread in North America; stable, secure population.

Black bears exist throughout most of North America north of central Mexico, except the desert region of the southwestern United States, from north-central Alaska across boreal Canada to Labrador and Newfoundland, and south to central California, northern Nevada, northern Nayarit and southern Tamaulipas (Mexico), and Florida (Wozencraft, in Wilson and Reeder 1993). However, the species has been eliminated from most of the Midwest by intensive agriculture and human settlement. Now it occurs primarily in remaining large forested tracts.

This species is known from many localities.

Locally threatened by habitat loss and interference by humans. Black market value of gall bladder and paws has led to an increase in the illegal harvest of this species.