Osteophagy by the Grizzly Bear,Ursus arctos

Abstract

Abstract A shed moose (Alces alces) antler eaten by a grizzly bear (Ursus arctos), which recently emerged from its winter den in western Alaska, contained 40.2% crude protein, 18.5% calcium and 8.5% phosphorous by dry weight. Bears emerging from dens could be experiencing skewed Ca:P ratios resulting in an appetite for bone phosphorus. Protein availability at this time of year in the Andreafsky Mountains may also be limiting. Antlers as part of bear diets may be seasonal, but can be a valuable source of minerals, especially Ca, P, and protein early after den emergence or other critical periods. Grizzly bears can obtain a valuable amount of nutrients by consuming the distal palm ends of shed moose antlers. Distal ends of antlers have thinner cortex where bone material is easier to break than at the antler base. In addition, the greater proportion of spongy bone in antler palms should be easier to digest by bears. The significance of shed antlers to bears as a mineral and protein source is still unclear, bu...