is a wire fence possible? sounds like a rodent- rabbits,marmots(groundhogs) or some such beast I've used stucco wire quite successfully to deter similar attacks make sure you know the size of the critter(tracks) u may need a finer mesh wire if it is mice or voles good luck hair and urine(human or predators like wolf,cougar etc)but blood attracts bears which will dig up the plants so I would avoid blood