@amaranth@weirder.earth had asked about werewolves yesterday. I have this theory that most shapechanger stories solve towards canines, since we're looking for animals that might scavenge close to human habitation and get spotted - foxes, wolves, coyotes, though hyenas and even (if you're at sea enough) sharks. In the preindustrial world, in the dim light between houses, you can't be sure if the animal you see out there in the dark is your neighbor.