St Patrick drove out werewolves from Ireland?

I was watching a doentary that was part of the extras on the director's cut of Underworld. They had one scholar they were interviewing who said that St Patrick didn't drive out snakes since they were really werewolves, thus the predominance of the lore in that area. That was the first time I had ever heard that. I had heard before many places that the snakes were actually Pagans, but never werewolves. Was he pulling this out of thin air or is there fact to it at all?