Dogs and puppies most prone to territorial aggression include those bred for herding and protection, such as shepherds and terriers. They protect “their” property (the house, other animals, car, yard, you) no matter who is present.
For instance, Rex may “protect” your bedroom so vigorously, that you can’t make a trip to the bathroom at night without risking his teeth. Boundary confinement such as a fence or chain makes territorial aggression worse. Territorial aggressive pups can trigger on family members or strangers. They can be part of a pack that learns to mimic the bad actor’s behavior en masse.
Solving Territorial Aggression
- Change the pup’s mood with pleasant words or commands that prompt him to concentrate on something else. His brain can be aggressive and protective when he's in a happy playful mood. For instance, ask him to sit or another command and reward with a favorite toy like a ball. When he has something to hold in his mouth, it's less likely he'll use his teeth to bite.
- Make high-trigger areas such as the front door, bedroom, or kitchen off limits.
- Use a baby gait to keep him out from underfoot. That still allows him to see into the room to “protect” you or the other pets.
Make Friends With the Mailman
Puppies and dogs that bark, lunge and growl at people on the other side of the fence are rewarded when the mailman, other animal, or your fiancé leaves. Change the outcome by enlisting the aid of the delivery people, neighbors and paperboy, and staging events. Here's how.

