We observed differences in den types, den site characteristics, and chronology of denning between radiocollared brown bears (Ursus arctos) and Asiatic black bears (U. thibetanus) on and near the Sikhote-Alin Biosphere Zapovednik in the Russian Far East during 1993-2002. Of 27 Asiatic black bear dens, 17 (63%) were in hollow trees, 6 (22%) in ground nests, 3 (11%) in caves or under rocks, and 1 (4%) was in an old excavated brown bear den. Of 12 brown bear dens, 9 were burrows excavated into hillsides, 2 under rock outcroppings, and 1 was a ground nest. We compared elevation, percent slope, aspect, and location on slope of 20 brown and 31 Asiatic black bear dens between species, sexes, and with 100 random coordinates, used to represent availability. Brown bears denned at higher elevations and on steeper slopes than Asiatic black bears and selected higher elevations and steeper slopes than were generally available. Black bears selected flat areas more often than available. Female black bears emerged from dens later than did males, and female black bears with cubs emerged later than barren females. One brown and 1 Asiatic black bear abandoned dens in response to investigator disturbance. While in dens, 1 Asiatic black bear was killed by a tiger (Panthera tigris) and 2 other Asiatic black bears survived predation attempts, one by a tiger and one by a brown bear. Tree dens may be important for Asiatic black bears for protection against predators. To increase survival and reproduction, we recommend protecting potential den trees from logging and adjusting hunting seasons and practices to reduce mortality of adult females.
- Volume 14
- Issue 2
- Pages 153-161
- Publication Date 1 January 2003
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- File Size 387.46 KB
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