Types of Dog Aggression
There are two main types of dog aggression: aggression directed toward dogs or people within the home and aggression directed toward dogs or people outside of the home. Most often, canine aggression is related to fear. This is most common with any situations involving strangers, strange dogs or strange objects, such as skateboards. Most aggression that takes place toward dogs and people within the home is caused by some form of territoriality or resource guarding.
Controlling Canine Aggression
No matter which type of aggression you are dealing with, a status-reduction program is a necessity. The owner-canine bond needs to be strengthened before any type of behavior modification can begin. This doesn't mean aggressive corrections, which studies have shown to increase aggression.
Instead, you should make your dog work for all of his resources. No more feeding meals from a dog bowl. Your dog should be handfed his meals every day for at least two weeks, depending on the severity of the problem. Your dog should earn handfuls of food by performing behaviors that are difficult, such as grooming or allowing other dogs to walk by.
In addition to the feeding, you should make the dog work for everything he loves. If he solicits petting, he must sit first. He may only get on the furniture when requested and must sit quietly before walking out the door for walks. This reduces your dog's status and puts you in control.
Your dog should also have a "timeout" place where he can go to calm down. A crate can work for this, or a quiet room at the back of the house where he can't bark at outside noises. You should send him to this place when he is reacting or after a difficult session to allow him to calm. Then, start sending him there when you notice the early onset of behavior. Soon, he will learn to go there before he reacts! Respect that place and don't let scary distractions bother him in that space.
Focus Command
The most important behavior to teach is "focus," or "look at me when you hear the command," such as "watch" or "look." Teach this in the most quiet room of the house. Say the word and hold a treat to your eyes. If your dog looks, he receives the handful of food. After three to five repetitions, stop moving the treat up to your eyes and wait for your dog to initiate the behavior. If he hasn't done this in 15-20 seconds, use the lure. Wait longer and longer each time. Once the dog does the behavior on his own, give three handfuls of food, one after the other, and lots of praise.
When your dog is doing this behavior reliably in the quiet room, move to a louder room, then a room at the front of the house, the backyard, front yard, park and so on until the dog can perform this behavior anywhere. Now, this command can be used to redirect his attention from distractions. Use bigger rewards (chicken, liver) for tougher distractions. Remember when moving to a new location to keep the expectations low and stay far from the distractions, moving closer as the sessions continue.
Fear Aggression
In addition to status reduction, dogs who are experiencing fear need to develop a new association to those things they fear. For example, if a dog has a bad association with strange men, every time a strange man appraoches, your dog needs to be fed his favorite treat as the man passes. To do this effectively, the dog must be far enough away from the distraction that he won't react. Feed as long as the man is in sight and then stop. This is how your dog should receive his meals until he is wagging his tail every time a strange man comes into sight.
When dealing with aggression, the treats should always come from the owner initially. Once the dog allows strangers to pass with no problems, then you can solicite friends, relatives or strangers to participate by tossing treats and finally giving treats only if your dog approaches the stranger on his own.
Prevention
The best way to deal with aggression is prevention. Be sure to socialize your new puppy to everything before he is 16 weeks old: grooming, men, children, other dogs, lawnmowers, etc. It is much easier to prevent aggression than to control it.