Well, for one thing the Irish Wolf Hound used to be such a good hunter that the entire population of wolves in Ireland was wiped out. That having happened, the Irish Wolf Hound started to disappear and probably would have if not for the efforts of Captain Graham who saved the breed but in the process the Irish Wolf Hound was bred to breeds such as the Great Dane, Deer Hound and the Borzoi, that is probably when the mean streak was bred out.