If you want to get stuff from the beaver dam in a easy way, then you should wait until a beaver is on land then bola it, club or tranq it, put berrys in its inventory, and now your have a giant beaver as your pet. Now bring your beaver to a safe location and make it not follow you, and then go back to the place with beavers and do it all over again. Keep repeating until no beavers are left in the water and then the beaver dams are all yours! (I’m around level 50 and i did it)