Grizzly Bears
Wolves don't prey on grizzly bears because they are too dangerous for them. They are explosive enough to catch and kill a wolf in a charge.
Polar Bears
The bear would be brutally killed as a result of being knocked to the ground and torn apart if ten wolves all attacked at once, maybe injuring or even killing a few wolves.
Black Bears
The bear is stronger than the wolf in every way possible. They are larger than wolves. Actually, much heavier to be honest.
Siberian tiger
A tiger would easily win a fight against a wolf. The tiger weighs almost three times as much as a wolf, tipping the scale at 600 pounds.