include black Some 3.5 million years ago the bear they call Protarctos abstrusus lived in a warm, wet habitat on Ellesmere Island in today’s Nunavut. The bear was previously known only from one fossil tooth found in Idaho. But in the Arcyic Rybczynski, a paleobiologist from the Canadian Museum of Nature, found most of a skull, a large part of the skeleton, and the lower jaw of a second bear.The whole thing was mummified, she says — preserved in a frozen peat deposit, though not acidic so the bones did not dissolve. Researchers have been searching the site for 20 years.And the specimen is a close relative to the ancestor of all modern bears (except pandas). It’s about the size of a black bear in our own region, or a little smaller.But it has cavities, likely a result of eating sugary berries. Modern bears also eat wild berries and apples, especially when they are fattening up to prepare for hibernation.Views of the lower cheek teeth and jaws of proarctos bear from 3.5 million years ago. MUSEUM OF NATUREIn a sense, cavities shouldn’t be there. They raise the question of why a bear was not better adapted to eating the normal, natural diet in its habitat — and why they still are not today. Bears today still get cavities.“We have not (studied) that, but it’s something that has definitely crossed my mind,” Rybczynski said. “I thought: You guys have been doing this for a long time! And that will kill you if you get infections in your teeth and your jaw.“Dental cavities are actually rare in wild animals,” she said. “For example, a previous researcher had looked at over 3,000 specimens of carnivorous mammals from North America. He found none of the carnivores had cavities, except for some of the bears.“We certainly see cavities in modern bears, so they haven’t solved the problem.”The bear’s habitat was like a northern forest today, and the site has all kinds of ancient specimens well preserved.“The wood that we found there — you can burn it. You would have thought I just took it out of Gatineau Park.“We have pieces of tree, we have cones, we have hundreds of different plants, so it’s a very diverse forest environment.” They also have a “structure” of wood and bite marks that match ancient beaver teeth found in the area. There’s a giant camel fossil nearby.“It’s an amazing, amazing beaver site.”