Bears of the Pleistocene

[brotherbear]

In the Shadow of the Sabertooth by Doug Peacock.

Spanish paleontologists measured a small number of bone pieces and fragments from short-faced bear fossils and inferred that the bear was not short-faced, long-legged, or predacious. A question, which was not asked, is what determines what a bear eats? The answer is behavior, especially aggression, not snout size nor the cut of their omnivore teeth. Animal protein is universally preferred over vegetation. Aggression and dominance no doubt played a huge role, especially around the kill sites of Pleistocene carnivores. Predation among modern bears is opportunistic.

The study purported to compare A. simus to the grizzly bear, implying the short-faced bear was a slow moving vegetarian. But grizzlies can outrun racehorses over a short distance and bring down adult elk, caribou, moose and the calves of all these creatures. The short-faced bear evolved in an America without people - grizzlies did not. From my own observations, brown bear routinely displace wolves, cougars and, less commonly, humans from carcasses, presumably because the bear has reason to fear humans. The short-faced bear had no reason to fear H. sapiens because it had never seen one until the late autumn of its species some 13,000 to 30,000 years ago.

Other paleontologists studied the teeth, along with some skeletal morphology, of A. simus and concluded the bear's diet largely consisted of coarse foliage by unselective grazing. I ended up wondering how any bear could survive the Beringian winter by unselected grazing of coarse foliage.

Sometimes paleontology raises important qualifications in characterizing A. simus as the once-dominant predator in North America. A useful study suggests that because the short-faced bear was incapable of sharp turns or of stopping on a dime ( based on examination of fossil skeletons ), it was therefore not a fierce or pursuing predator. The bear's gracile bone structure argued against wrestling with a mammoth or giant sloth. Having had the opportunity to handle a museum specimen myself, I couldn't agree more that this big-hipped, broad-nosed bear with huge crushing jaws was a superbly equipped scavenger. On a continent crawling with giant predators and prey, carcasses would have been commonplace. The short-faced bear would certainly be a main contender for any kill by any animal within its olfactory range. The large hipbones hint at an animal that could, like a grizzly, stand and scent carrion from several miles away. Modern grizzly bears have been recorded scenting carrion at a distance of nine miles. Standing on its hind legs to reach 15 feet tall, with its wide nostrils flaring, the short-faced bear might have been capable of smelling a carcass at a much greater distance. Reply