beavers slap their tails to warn each other of danger and when they dive under. I'm a trapper and this is what it sounds like to me. Even a small beaver can make a big splash
i think a partially serrated edge , spear or drop point, simple carbon steel around 58rc, micarta/stabilized wood, kydex sheath although those hollow tube handles with emergency supplies like matches would be awesome too, possibly even a sawback