Denning ecology of barren-ground grizzly bears in the central Arctic

Abstract

Between May 1995 and June 1999, we studied denning ecology of 81 barren-ground grizzly bears (Ursus arctos) equipped with satellite radio-collars within a study area of 235,000 km2, centered 400 km northeast of Yellowknife, Northwest Territories, Canada. All dens were located on well-drained slopes (X̄ = 25.3°, SE = 1.20, n = 55). Choice of den aspect was nonrandom (X2 = 12.4, d.f = 3, P<0.01, n = 56); the majority of dens faced south (25), followed by west (13), east (10), and north (8). Most dens were constructed under cover of tall (>0.5 m) shrubs (Betula glandulosa and Salix), the root structures of which supported ceilings of dens. Selection of denning habitat by bears was significantly different from random (G = 127.67, df. = 6, P<0.0001). Bonferroni confidence intervals indicated that esker habitat was selected more than expected by chance (P<0.10). Den entrance occurred primarily in last 2 weeks of October. The majority of bears emerged from dens in the 1st week of May.