The next 4 pictures are in the sequence of when big boy snuck up on the bear at the falls and pushed him to the bottom of the river and held him there. This is the first shot when he surfaces to meet his nemesis.
He is "drowned rat" mad I'm telling you.
This was a vicious confrontation as you can see from the reaction from the bear on the left. The large male on the right quietly came up from behind the other bear as he was intently watching for a fish at the base of the falls, and then suddenly jumped full force up on his back, forcing him deep into the rushing water. When the fishing bear finally got himself up out of the water the battle was on.
