Bears of the Pleistocene

[brotherbear]

In the Shadow of the Sabertooth by Doug Peacock.

The reason grizzly remains are seldom found is probably because many of them die natural deaths in their dens. Brown bear are healthy mammals who heal well and rarely succumb to disease. They may live beyond 30 years. Human-caused mortality accounts for most modern bear deaths. Uncommonly, grizzlies are known to use caves to sleep out the winter, but suitable caves are rare and only locally available, usually in limestone topography. Before the short-faced bear succumbed to extinction 13,000 years ago, some of those caves were no doubt already occupied. So the brown bear digs dens.

On rare occasion, brown bears have stayed out of the den all winter by appropriating the deer kills of cougars or elk kills of wolves - much like the short-faced bear must have scavenged his way through the Beringian darkness. But the grizzly is not an effective predator. This carnivore cannot subdue enough large animals to keep itself alive in winter.

My suspicion is that most grizzly deaths in the wild take place during hibernation, a natural burial in the remote country where brown bears normally dig their dens. Back when both grizzlies and short-faced bears roamed the country, brown bears were not at the top of the food pyramid. The smaller grizzlies would be at a disadvantage trying to compete at a mammoth carcass and could not survive without denning. In coldest Beribgia, this competitive drawback could suffice to drive grizzlies south. Reply