Who would win a fight between a grizzly bear and a bull?

It depends on the scenario and the incident of the fight. A grizzly bear has sharp enough claws to pierce into the bull's head and swat that thing to death. If the bull charges and gores the grizzly bear with those horns, it would win the fight against the grizzly bear.

Answer 2:

A grizzly would not dare take on a big bull in a natural environment. And a bull, like all prey animals, would rather run the other way than take on a great bear like a grizzly. But if a fight should occur, a bull, if he has horns, would gore the bear in the ribs, or if he's not horned, would crush the bear's ribs with his head to the point that the bear may die soon after. The bear will try to claw at the bull with his long claws and bite at the throat, but the dewlap on the bull, not to mention the bull's thick, muscular neck, would protect him from serious injury. Thus, a bull would win.