What are black bears enemies?

A black bear's natural enemies are grizzly bears and wolves; however, men and dogs are also enemies to black bears. All bears seem to lack the ability to commit to a target, so even two dogs can run the largest of bears to a state of exhaustion. Polar bears have been known to get over-heated and faint while being harassed by sled dogs - after which all the musher has to do is walk up with a harpoon and kill the poor beast.

Other black bear sows with cubs, possibly cougars, possibly wolves, man, grizzlies.