shoot them
Humans, primarily. Bears and wolves may also attack cougars, but never to hunt and kill them.
Bears and wolves are known to kill cougars. Large alligators may eat cougars.
People are the biggest thing. Wolves, Bears, and sometimes mountain lions will kill a moose.
Black bears, grizzly bears and wolf packs will occasionally attack and kill cougars.
No because in the past, mountain men used beavers traps to do this and it's not hard at all
Brown bears are and are not mountain bears. There is no species of bear called the "mountain bear" anyway. All you have are grizzlies, black bears, brown bears and polar bears. So it really depends on what you mean by "mountain bears." Location helps a lot too, as you could refer to the "mountain bears" of the Adirondack or Appalachian mountains, or the bears that live in the Rockies and Sierra Nevadas.
They don't really have preadotors besides us
Grizzly bears are the biggest predators in their environment. Even wolves and mountain lions can't kill grizzly bears because the Bears are well armed with their size, strength, claws, and teeth. However, grizzly bears can be a threat to each other; in particular, males often try to kill cubs so that their mothers will be ready to breed sooner.
The mountain lion has no natural predators. He's pretty much left alone and most will die of accidents or old age.
they only kill other bears because they do not want them to hurt their babies
bears and mountain lions
The male is more known to do this, although females bears can and do kill their young.