Grizzly Digs Out, Eats Sleeping Black Bear Biologist Can’t Find Precedent For Attack On Hibernating Bear

A grizzly bear dug a hibernating black bear out of its den in the remote country of northwestern Montana last month and ate it in what a wildlife biologist says may be the first such case ever recorded.

Diane Boyd-Heger, a wolf researcher, plans to publish an article about the incident as a scientific paper.

Her husband, Ed, and his dog, Beaner, stumbled on the grizzly one day in November during a walk near their cabin, apparently while it was still eating the smaller bear. The grizzly charged Heger, but veered away at 15 feet when he blasted it with bear spray.

“The speed at which that bear came out of the woods was unbelievable,” Heger said. “There wasn’t time to get scared.”

It was not until two weeks later that the couple discovered the unusual nature of what Heger had stumbled upon. He had returned a few days after the encounter, but the dog signaled that the grizzly was still around, so he did not stay.

Boyd-Heger said the grizzly ate the much smaller black bear “to the toenails.”

“There were only a few bone splinters left, and there weren’t really any signs of scavengers,’ she said. “The grizzly sat there and ate it all.”

Only one end of a femur was large enough to take to the animal museum at the University of Montana for comparison purposes.

The grizzly’s 9-inch-long hind pawprint indicated it weighed 250 to 300 pounds, probably a subadult male or an adult female.

Boyd-Heger said she called all the bear researchers she knows and could find no one who had ever heard of a grizzly excavating and consuming a denned-up black bear.

Boyd-Heger has spent 18 years in the North Fork studying wolves and, less so, coyotes - “and inadvertently, mountain lions and bears.”

She said black bears tend to den about a month earlier than grizzlies, and this grizzly probably was looking for a last load of calories before going into its own hibernation.

“I imagine the denning bear was somewhat lethargic,” she said.

The black bear had dug its den in a big, 20-year-old slash pile near Heger’s cabin on the edge of Glacier National Park. The grizzly tore through the top of the pile to drag the black bear out, then dragged it to nearby woods.

Both Boyd-Heger and her husband agreed that he should not have followed the blood trail and tracks that he spotted at the slash pile.

“Ed didn’t know it when he started following the drag trail, but the grizzly bear was right there on a fresh kill,” she said. “The bear’s reaction was very normal and completely justified. Ed was in his territory.”