I heard a story from my paddling buddies of a rabid beaver once attacking kayaks and canoes. It is pretty rare for beavers to get it. There was one in FL: https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5122a3.htm Those guys can get pretty big on their own without mutations, and the tail-slaps are intimidating. I'd try to make friends with the giant beavers.