Naturally occurring fights are some of the coolest instances of competition outside of sports. You can understand what the Romans were trying to recreate in the Coliseum. These are two big bears looking for food before they gotta go hibernate. This is a heavyweight bout of two big badass bears. Those guys went at it and left it all out in the forest. Honestly, this looks very reminiscent of an Oline-Dline 1on1 drill. The one bear hiding behind the tree and resting is also hilariously human.
Now could one of these fight a gorilla? I am going to be honest, if this is how bears fight in those drawn out intervals, a Gorilla that brings the heat with some A+ cardio might be able to take em down.
Here is my point of reference. Even though the bears fought for 40 seconds, it was a lot slower than this 9 seconds swingfest these gorillas had. Gorillas might just want it more. Sadly we will really never know.