In the story Bisclavret by Marie de France, the King is a werewolf. He would go off into the woods for three days at a time, once a month during the full moon. No one knew where he would go, not even the Lady. One day she asks him where he goes, and he tells her that he goes into the woods and turns into a werewolf for three days, where he feeds upon whatever prey her can find. He tells her that his only weakness is that if someone were to find his clothing while he was in the form of a werewolf, he would remain in that form and never be able to return. However the Lady betrayed him, and sent a knight (whom she loved) to go retrieve her husbands clothing, and for a year he didn't return. Until their anniversary he returned to harm the couple.
The TV show Supernatural, werewolves are depicted in a similar way as in Bisclavret. The werewolves, however, are men and woman. They always have sharp teeth and claws, and most often feed on humans. These werewolves also have a very unique feature, they always consume the heart of whatever they are eating. This is interesting to me, as I believe the show is trying to make a statement about werewolves, and that they are ruthless killers out for blood. Both Bisclavret and Supernatural depict werewolves as ferocious creatures who transform into wolves in the full moon.