My dog, who is in every other situation a pussy cat, is over defensive and aggressive when it comes to territory. Especially in his yard and while inside the car. I've heard that territorial dogs are more prone to bite.
Every lovable canine has natural instincts to guard the pack's boundaries.
It is instinctive for canines to bark or even growl at strangers when confined to a yard or automobile. However, this aggressive behavior can often lead to more severe problems if not handled correctly. Most territory aggression problems can be successfully controlled with intensive and regular socialization exercises. Teach your canine companion to walk on a loose leash around other people and dogs. Join a group obedience class.