I sometimes wonder if some of the references to the mythical beasts like fire breathing dragons are simply, some now extinct species of animal with embellishments like fire breathing. Lets face it, oral tradition came with a certain degree of embellishment and we know dinosaurs used to exist, but what's the chances of finding the remains of an extinct animal if we tried to look for it? Perhaps the Dodo would be an exception as, iirc, they last lived on an island somewhere killed by sailors for food, but hopefully you get my point. I doubt many skeletal remains would be found with Anglo-Saxon remains because none have been found so far, but do archaeologists looking for Anglo-Saxon remains ignore animal remains during the dig process? Its not something I'm familiar with.