Bear v. Tiger? In Siberia, the bears live in trees so that the tigers won’t get them, but those are just little black bears.
The Eurasian brown bear, found throughout most of Siberia, weights up to 1000 lbs. Not an unreasonable match against even a Siberian tiger, which top out around 700 pounds.
The problem with the exercise is that in the wild it’s difficult to imagine a scenario in which either beast would want to engage in such a battle.