Grizzly Bear, Ursus arctos, predation of a denned adult Black Bear, U. americanus

During a radio-tracking flight to document denning activity of Black Bears (Ursus americanus) in interior Alaska, a Grizzly Bear (U. arctos) was seen actively digging at the den of a radio-collared adult female Black Bear. Subsequent investigation of the site revealed numerous bone fragments and a chewed radio-collar indicating predation. The den showed a second entrance where the Grizzly Bear had been digging and was successful in forcing the Black Bear to flee and be killed in the area immediately adjacent to her den.