Dr. J. Michelle Posage and Dr. Amy Marder
If you have ever been bitten by a dog, you are certainly not alone. More than 2 percent of people in the United States are bitten each year – that’s more than 4.3 million people! But what causes aggression and how should an owner handle it in dogs?
Aggression in dogs is defined as a threatening or harmful behavior directed toward another living creature. This includes snarling, growling, snapping, nipping, biting and lunging. Dogs that show such behavior are not abnormal; they are merely exhibiting normal species-typical behavior that is incompatible with human lifestyle (and safety). There are many reasons why a dog will act aggressively toward strangers or even his owner.
The first step, when attempting to find out why your dog is being aggressive, is to take him to your veterinarian. Some veterinarians will visit you at your home - but dogs tend to be more aggressive on “their” territory. If there’s no medical cause for the aggression, your veterinarian may refer you to a behaviorist, who will then obtain a full behavioral history and recommend therapy.
Even if treatment appears to be successful, you should always be on guard. The frequency and severity of aggression may be reduced but, in most cases, aggression cannot be eliminated completely. You must weigh the risks of keeping an aggressive dog against the benefits. Remember, safety for yourself and people around you is the primary concern!
In the course of a veterinary examination, your veterinarian will determine if there is a medical reason underlying your dog’s aggressiveness. For instance, a dog with neck pain may show aggression when pulled by the collar.
Once medical causes have been ruled out, your veterinarian will refer you to a behaviorist. At the behaviorist’s, you’ll be asked to answer many detailed questions regarding your dog’s behavior. The session may last a couple of hours. An accurate description of your dog’s behavior is necessary. Keeping a journal is helpful. You should note:
- What elicits the aggression
- How often it occurs
- To whom it is directed
- The specific behaviors
- The dog's postures at the time
Videotaping your dog’s behavior is helpful for the behaviorist, but don’t get hurt while making the video. Answers to the many questions asked can lead the behaviorist to establish the cause of the aggression, and then outline an individualized approach to its treatment. The behaviorist will also provide a professional opinion of the risk involved.
Aggression is influenced by several factors, including: genetic predisposition, early experience, maturation, sex, age, size, hormonal status, physiological state and external stimuli. Behaviorists use a classification system based on patterns of behavior and the circumstances in which they occur. This is done to determine the dog’s motivation and the cause of the behavior. The classification is as follows:
- Dominance-related aggression is one of the most common types of canine aggression that behaviorists treat. The aggressive acts are directed toward one or several family members or other household pets. Dogs are pack animals, and they relate to humans as members of their own species and pack members.
- Territorial aggression is directed toward approaching animals or people outside of the pack in defense of a dog’s area (home, room or yard), owner or fellow pack member.
- Inter-male aggression between adult males usually involves territorial or dominance disputes. Inter-female aggression occurs most frequently between adult females living in the same household.
- Predatory aggression is directed toward anything that the dog considers prey, usually other species, but sometimes any quick-moving stimulus, like a car or bike.
- Pain-induced aggression is caused by a person or animal that causes pain. It often occurs when a person attempts to touch a painful area or when injections are given.
- Fear-induced aggression occurs when people or animals approach a fearful dog. This is common when the dog cannot escape, and is sometimes seen when an owner uses severe punishment. Active, unpredictable children may also stimulate this type of aggression.
- Maternal aggression is directed toward anyone that approaches a bitch with puppies or in false pregnancy.
- Redirected aggression occurs when a dog that is aggressively motivated redirects the aggression from the source to another. For example, a dog that is barking at the door may redirect his aggression onto an owner that is pulling him back. Dominant dogs often redirect onto subordinates.
Treating aggressive behavior may involve a combination of behavior modification techniques (habituation, counterconditioning and desensitization), drug therapy, surgery (such as neutering/spaying), avoidance and management (such as leash or head halter). Each case is unique, and the success of treatment varies depending on the diagnosis and in accord with your capability, motivation and schedule.
Even with successful treatment, however, there is no guarantee that the aggressive behavior won’t return. In most cases, the frequency and severity of aggressive behavior can be reduced but the aggressive behavior cannot be eliminated completely. The best that may be hoped for is to reduce the probability of aggression. You must weigh the risks of keeping an aggressive dog against the benefits.
If your dog is unpredictable, consider using a comfortable basket-style muzzle until you can get professional help. Until you receive professional help, avoid all interactions that trigger your dog’s aggression. Do not attempt physical punishment. This can increase the intensity of your dog’s aggression and may result in serious injury. Avoiding problems may involve:
- Keeping your dog confined in a separate room when visitors or children are present
- Housing or feeding your dogs separately if they are fighting with each other
- Removing objects like bones or rawhides that your dog may be guarding
Do not allow children to have unsupervised access to your dog. Children should be taught to avoid interacting with dogs that are eating, chewing on a bone, or resting. They should not be allowed to tease or hurt dogs.
Keep your dog on a leash at all times. In the home, you may want to attach a thin nylon leash on a buckle collar, which your dog can drag comfortably. This will give you safer control over him. Indoor leashes can be attached to head collars for even greater control. If your dogs are fighting, do not get in the middle. Interrupt the aggression using water, a loud noise, blanket or spray.