I feel like Lorne Greene watching this video, I mean it's very rare to catch a video like this in a human inhabited area.  Fun fact, I loved New Wilderness as a kid and would watch it religiously.

The video starts off with both bears doing a lot of posturing and trying to intimidate each other.  It eventually turns into a full on bear brawl.

They seem to be evenly matched and then one bear goes into full Brock Lesnar mode towards the end.