Aggression

What is it?

Aggression can be a normal way for dogs to communicate, but it is a serious and potentially dangerous behavior problem. There are many types, including fear-related (one of the most common), conflict-related, possessive, protective or territorial, maternal, play-related, redirected, pain-induced, and aggression linked to medical problems. Many dogs show more than one type, and learning plays a part in all of them: when aggression makes a threat go away, the behavior is reinforced.

What signs should I watch for?

Warning signs include growling, snarling or lifting the lips, snapping, and lunging, and a fearful dog may also show fearful body postures. Note when and where the behavior happens, who or what it is directed at, and what came before it. Aggression that starts suddenly, at any age, or that does not fit a clear pattern may have a medical cause. Pain from dental disease or arthritis, fever, fatigue, or loss of sight or hearing can make a dog more irritable, and conditions such as hypothyroidism, epilepsy, and rabies can cause aggression.

How is it diagnosed and treated?

Start with a veterinary exam to look for pain or illness. Diagnosing the type of aggression, judging the chances of safe improvement, and building a treatment plan are best done with a board-certified veterinary behaviorist or an applied animal behaviorist. Treatment usually combines safety management, behavior modification, and sometimes medication prescribed by your veterinarian.

Do not try to fix aggression with punishment. Punishment and frightening experiences can make fear, and fear-based aggression, worse. If your dog growls, snarls, snaps, or lunges, calmly move away and do not try to take things from them; keep people and pets safe until you have professional help.

Can it be prevented, and what's the outlook?

• Early positive handling and socialization of puppies may help prevent some problems, such as guarding food or toys.
• The outlook depends on the type of aggression, its triggers, and how safely it can be managed.
• Decisions about living with a dog that has bitten are serious and can have legal consequences, so work closely with your veterinarian and behaviorist.