Both brains and brawn, each dog is different in they're own way, I suppose you will never get two the same. had a bitch that didn't like other dogs, this one doesn't like strange people very much and my other two halfx are sound, if another dog shows any aggression what so ever to either of them they won't hesitate, (Ticking time bombs) when out with others who have aggressive dogs. The firstx is the one on the right. I tried to put better pictures up but were to big. Type in wheaten in the search bar at the top right hand side of the page and select forums, should bring up the past pages on t