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:
Genetic predisposition. Some breeds have been selectively bred for protective
behavior.
Insufficient social experience. A dog who had few opportunities to interact with
other dogs and people as a puppy may overreact to strangers as an adult.
Maturity. Some dogs are quite friendly as puppies but begin displaying guarding,
threatening, and other aggressive behaviors on reaching adulthood (between 2 and
3 years of age).
Unwitting encouragement from owners. Many people don't realize that if they try
to soothe and reassure their dog when he gets belligerent, they're reinforcing
the behavior. Other owners back off at any sign of aggression toward themselves,
teaching the dog that he is in charge.
Territoriality. A dog may guard his bed, toys, food, house, yard, family
members, car, and the street he regularly walks on. In a new environment he may
react aggressively to anything approaching him and even to being looked at by
another dog or a person.
Dominance. Aggressive behavior may arise during encounters with other dogs in an
effort either to assert dominance or to resist being dominated. Similar status
conflicts may also crop up between a dog and his human family members.
Roughhousing. Play fighting between puppies is normal and includes playful
growling, chasing, nipping, poking, biting, and wrestling. All this fun helps
puppies figure out their place in the pack. Older dogs enjoy play fighting, too;
it's a way to bond and get exercise. But if a roughhousing person gets into the
mix, aggression can escalate, particularly if the dog wins the match. Innocent
rough play between person and puppy can develop into serious aggression as the
dog matures.
Inability to escape. A dog who's cornered or tied up will react much more
strongly to a perceived threat (such as a stranger approaching) than he would if
he were free to move away.
Pain. If a dog is sore or has an injury, he may react aggressively if someone
touches that part of his body. This is a reflexive response caused by pain.
Senility. Confusion or diminished senses (such as smell and sight) may interfere
with an older dog's ability to recognize people, to anticipate being approached
or handled, and to judge whether he's safe in a particular situation.
Predatory instincts. Dogs are hunting animals. Most have an innate urge to chase
anything moving away from them, whether it's a tennis ball or a delivery truck.
Behaviorists don't classify hunting and chasing as aggressive behaviors unless
they are directed toward people.
Training Tips
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:
Make a list of your dog's favorite things: walks, meals, toys, treats, chasing
balls, getting brushed, and so on. Every time you want to do one of these nice
things for him, command him to “sit” or lie “down” first. It's as if
you're having him say please.
Remember to praise him every time he obeys you. Your feedback lets him know he's
on the right track.
Be consistent about showing him that you - and other human members of the
household - control all the valuables in his life. To get what he wants, he must
first do something you request. This call for a firm change in your behavior -
not just for a few days but for the rest of his life.
Don't allow him to rest on your bed, the couch, or any elevated surface (the
position suggests higher status). If you can't bear not to let him up, make him
sit for you first.
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.