Dogs have a normal, inherited drive to defend their territory, and most dog owners want their pet to alert them when someone comes to the door. Problems arise when this drive is extremely strong and the dog growls, lunges at, or bites visitors. The problem is compounded when the dog learns that it can frighten away visitors, as most people confronted with a growling or snapping dog quickly back off. Once the dog learns how effective aggressive behavior can be, it increases in intensity and becomes more difficult to eliminate.

Dogs express territorial aggression in many ways. One dog may bark aggressively, growl or lunge at visitors. Some dogs calm down once the visitor is in the home, but threaten if they move quickly or approach the owner. Dogs that wag their tail while growling are torn by two conflicting desires. They want to greet the person, but also to warn him off. These dogs are particularly dangerous because many people mistakenly believe that a dog wagging its tail will not bite.

Territorial aggression is often first noticed when the dog is 6-7 months old. The dog may be friendly on neutral territory, and is often protective of only one specific thing, the car or the backyard, for example. Fear may be combined with territorial aggression. A fearful dog growls, but backs off if approached. However, when the person turns his back and presents a less fearful stimulus, the dog's territorial aggression overcomes its fear, and it may bite the person on the back of the leg or the ankle.


1. The dog inherits a drive to protect its territory from its parents. The intensity of this drive varies between individuals. Problems occur when the drive to protect territory is very strong. Because the drive to protect is inherited, it is difficult to alter.

2. Territorial aggression problems are often exacerbated by learning. The dog learns that if he growls at people they will go away. Yelling at the dog or punishing him will not prevent the behavior, but will often increase aggression.

3. Although the behavior may be seen in both male and female dogs, dominant male dogs are most likely to exhibit territorial aggression.

4. Excitement usually makes territorial aggression problems worse.

5. The size of the territory seems to have an effect on the expression of territorial aggression. Dogs that are confined by a short chain often show more intense signs of territorial aggression than those on longer chains. Some dogs are aggressive when walked on leash, but are fine when heeling off lead. The short leash may be similar to a short chain, and by restricting the dog's territory to the person walking him, make the dog overly protective of that individual.


Generally, it is easier to train the dog to do something acceptable than it is to punish him or correct the wrong response. You might decide to teach your dog to sit or lie down quietly beside you when he is in a situation which elicits aggressive behavior (systematic desensitization), or to do something which is incompatible with the unwanted behavior, like go to his bed and lie down (counterconditioning).

Once you start training, it is important that you prevent your dog from ever showing aggression again. Any time that he manages to perform the unwanted behavior, you set the training program back by weeks or months. Confine him to a room or a crate, put him outside, or put him on a leash in situations in which he is likely to be aggressive.

Castration does not reduce territorial aggression. However, it is a good idea to castrate aggressive dogs to prevent them from passing this inherited characteristic on to future generations.

Technique # 1 Counterconditioning

This technique will allow you to train your dog to do something that is incompatible with the aggressive behavior. Most people like to train their dog to go to his own bed and lie down, because he can't do this and attack people at the front door at the same time. If you train your dog using this technique, you will be able to control territorial aggression while you are present. Your dog may still exhibit the unwanted behavior when you are not around.

You must first train your dog to go to his bed on command. Have at least two short training sessions of 10-15 minutes every day. Give the command BED, and when the dog goes to it (even if he just stands on it) reward him immediately (within 1/2 second!) with a treat like a piece of cheese or a cheesie. To maximize the speed at which your dog learns, give him a treat every time he responds correctly when you start training. Once he knows the command, make the behavior more consistent by rewarding him intermittently.

When the dog responds correctly to your command in a quiet environment, you can start training him to respond to the command when the stimulus which causes the aggression is present. Start by presenting the stimulus at a low intensity. For example, if your dog attacks people at the front door, have a friend walk up to the door and stand quietly without knocking. As soon as the dog reacts, blow a whistle to get his attention and give him the command you have chosen - when he goes to his bed, immediately reward him. When you start this new stage of training, you should reward each correct response until the dog is consistently responding correctly, before going back to intermittent rewards.

Gradually increase the intensity of the eliciting stimulus - train the dog to respond to your command as people approach the door, ring the bell, and enter. If the dog fails to obey you at any stage, return to the previous level and concentrate on training at that level of stimulus intensity until the dog is responding correctly, every time, before progressing to the next stage.

You should initially start out with food rewards, but if you say GOOD DOG immediately before
you give the food reward, the voice praise will eventually become a reward in itself. This reward IS easy to use, works in a variety of situations or at a distance. Voice praise may be used every time the dog performs correctly.

Technique #2 Systematic Desensitization

An alternative method of dealing with territorial aggression problems is to use systematic
desensitization to habituate the dog to the stimulus that causes aggression. A dog trained in this manner will not respond to the stimulus, whether or not you are present. Using this technique, dogs that have a combination of fear and territorial aggression can often be trained to remain quiet whenever the inciting stimulus is present.

First of all, you must train the dog to come, sit and stay, off the leash. Start training in a quiet environment with few distractions. Train using food rewards (many people find small bits of cheese or cheesies to be useful). The training sessions should be 10 or 15 minutes each, twice a day, and preferably separated by four hours. When you first start training, reward the dog for every correct response to your command, as this will ensure the fastest possible learning. Once you feel confident that he knows the command and the proper response, reward appropriate responses intermittently to make the behavior more consistent. Gradually increase the distractions in the training sessions, but if the dog fails at any stage, go back to the previous level until the dog is responding consistently.

Once the dog is sitting and staying reliably, you can train him to sit quietly beside you when strangers approach. Have the dog sit quietly at the door (or run, or in the yard, or wherever the aggression occurs). Have someone approach the house and stand outside the front door. Reward the dog for sitting quietly. Over many sessions, reward the dog as he is gradually exposed to and accepts the following:
- someone knocks on the door or rings the bell
- the door opens, but no one is seen on the other side
- the door opens, and the dog can see a stranger at some distance from the house
- the stranger approaches the house
- the stranger enters the house but stands just outside the door
- the stranger enters and moves into the house, as a normal visitor would

You should reward the dog for sitting quietly beside you throughout these steps. If the dog shows any aggression (barking, growling, etc.) stop the training session, ignore the dog for 5-10 minutes, and start the next session at a previous level where the dog behaved. If the dog is very threatening, you may want to put a muzzle on him while you are training him, to make your volunteer strangers feel more secure.

Regardless of which technique you use, it is useful to keep records. Training your dog can take several months, and it can be discouraging if you do not have records which show the improvement your dog is making. The headings of the chart could be similar to the following (after Victoria Voith):





# of Trials

Dog's Response

By Doctors McKeown, Luescher & Machum of the Ontario Veterinary College.