By Rolan Tripp, D.V.M.
The behavior: Physical attacks (including biting) on a person or another animal, or threatening behavior, including growling, snarling, snapping, loud rapid barking, and lunging.
Why dogs do it: Usually aggressive behavior arises from fear. The dog feels threatened by the presence or approach of another animal or a person and lashes out to defend himself. A dog may also display aggression to protect his territory (guarding the owner's house or car), to warn others away from his food or toys, or to assert dominance.
Aggressive behavior may be influenced by many factors, including:
Seek professional help. Aggressive behavior is a serious problem and requires a thorough yet swift response from owners. See your veterinarian first: A thorough medical evaluation (including a thyroid test) will show whether any physical conditions might be lowering your dog's aggression threshold. Next, consult a professional animal behaviorist, who will pinpoint circumstances that trigger belligerence and customize a treatment plan for your dog.
Keep a journal. Record all the occasions in which aggression occurred. Note exactly what happened right before, during, and after the flare-up, including who was present, how they responded, and the time of day. If you have a video camera, keep it handy for documenting incidents. Involve your entire household in the detective work. Show the list to a behaviorist.
Avoid provocation. Once you have your inventory of situations that set your dog off, share it with your household. You should all make every effort to avoid these circumstances. Don't let your dog practice his aggression skills! For example, if he's threatening when people come to the door, don't let him greet visitors; put him in a safe place, such as his crate (he should be properly crate-trained), and let him join in only after he quiets down.
Never punish for aggressive behavior. Punishment will only intensify your dog's fear, exacerbating the aggression. In tense situations, remind him you're the leader, command him to sit, and praise him for doing so.
Go through basic training. An obedience course will give your dog discipline as well as something constructive to do with the energy he's using to be aggressive. Once he responds consistently to a few commands for instance, he will sit to greet somebody you can put him through his paces whenever he might be getting snappish. This kind of work is also great for your relationship, reinforcing your position as leader of his pack.
Teach your dog respect. Your dog needs to know that you're the leader of his pack. If you play with him, give him toys and treats, and pet him no matter how he behaves just because he is fluffy and adorable why would he ever clean up his act? Here are some tips on how to show him you're top dog:
Spell out the rules of the game. You not your dog should always direct your play sessions. If you're going to play fetch, for example, begin by telling him to sit. When he does, throw the ball. Teach him to bring it back by offering to swap it for a treat. If he tries to play keep away, turn your back and ignore him until he drops the ball. Always be the one to end any game: Put the ball or other toy away, and tell him the game is over. Stop playing while he still wants more, before he gets tired and quits on his own. Remember: You are in charge.
Tools You Can Use
Gentle Leader. This head halter gives you better control of your dog than a standard collar does, and it even applies pressure in spots on the neck and muzzle that can trigger a more passive response. If your dog pulls or lunges while wearing the Gentle Leader, the leash will close his mouth and turn his head away from his target. You can prevent potential brawls by steering him away from dogs, kids, or other triggers before anything starts. Stop and change directions frequently, so your dog has to follow your lead.
Basket muzzle. If you must expose your dog to a volatile situation before he's trained to handle it, put a basket muzzle on him. He'll be able to pant and even bark, but he won't be able to bite. Use this device only in high-risk situations or while you're working on a treatment plan.
Balls and Frisbees. Aggression is often related to stress, and exercise is the universal stress reliever. Interactive play with a ball or Frisbee is great exercise and can strengthen your bond with your dog. If he's socialized, agility classes and other dog sports can also provide a fun workout for both of you.