Well, I know a guy who whooped a Rock Ape in a cage years ago. Back in the day when they had that kinda stuff at fairs. Pre-dates MMA stuff I guess.
He went back the following night and and hid in the back just to see how everyone else faired. The Rock Ape took a different approach that night, jumped around the cage throwing

at everyone

.
So using ricer math, if man can beat Rock Ape, but Silverback can beat Rock Ape, silverback or man with baseball bat maybe has a chance?
I think Bull Elephant takes Coastal Brown bear tho.