Our Shepherd is a family pet. He loves our kids (10 year old twins boy-girl) and they play with him constantly. My point is he is the most loving animal and now we have given him the roam of the house at 1 1/2 years old to watch over the house. How can I tell if this loving dog will viciously attack an intruder? Im just wondering if he's going to embrace a stranger at 3am in the morning.