Affected Animals:
Dogs. The highest incidence of dominance aggression occurs in intact males, followed, in decreasing order of frequency, by castrated males, spayed females and unspayed females. English springer spaniels, Lhaso apsos, cocker spaniels, Doberman pinschers, and toy poodle and terrier breeds have been reported to have a higher incidence of this type of aggression, but it can occur in any breed of dog.

Overview:
Dogs may become aggressive towards their owners if they perceive that their dominance is being challenged or that there is a threat to a "critical resource" such as food, a resting place, a prized object, a favored person, or anything else that is important to them. Owners seek professional advice about dominance aggression more often than about any other type of canine aggression.

The intensity of dominance aggression ranges from mild to severe. Dominance aggression develops around the time a dog reaches social maturity, which is about two years of age. Treatment involves life-long management using a combination of therapeutic techniques.

This behavioral problem, which is common among canines, can pose a safety threat to humans. Children that live in households with dogs that have dominance aggression are at greatest risk for serious or fatal injury.

Clinical Signs:

Growling, snarling, lunging, snapping or biting owners or other familiar people. The dog typically will have a dominant body posture.

Symptoms:
Owners frequently report that their dog becomes aggressive without being provoked. Usually, they are unaware that they have unintentionally challenged or competed with the dog. This is very understandable, since the trigger for the aggression can be something as subtle as petting the dog or looking at it.

Description:

Dominance aggression has its roots in the social organization of wolves, the closest wild relatives of domestic dogs. Wolves live in social groups called packs. Within the pack there is a social hierarchy in which each individual animal knows its rank in relation to every other animal. The dominant individuals have a priority to the critical resources of food, water, and resting places.

Dynamic, rather than rigid, the hierarchy is maintained through a complex communication system using signals of dominance and submission; thus, the social relationships within a pack of wolves are quite complex. One of the functions of the hierarchy is to reduce aggression within the pack. When the hierarchy is stable, overt aggression is minimized. Presumably, domestic dogs manifest dominance aggression when they perceive that the hierarchy within the household is unstable.

Diagnosis:

First, a complete medical history, physical examination and baseline laboratory work, including testing of the thyroid hormone levels, is recommended to rule out medical causes of aggression.

A specialist in veterinary behavior will ask owners for a history of the animal's behavior and will note the dog's age, sex and breed; this data is important because certain dogs, such as males that have not been neutered, are more prone towards dominance aggression than other canines. There is a breed predilection as well.

Next, a behavioral specialist will look first at the context in which the aggression occurs. Dogs that have dominance aggression may react aggressively to petting, hugging, being stared at, stood over, or disturbed while resting. Owners that command, scold, punish or force the dog to do something it does not want to do also may trigger aggressive behavior. In addition, aggression can occur when a family member attempts to interact with the dog when it is in the presence of food, prized objects, a favored person, or a preferred resting-place.

Because dominance aggression is directed predominantly toward the dog's owners and other familiar people who the dog perceives to be part of its family or "pack," it is important for the behavioral specialist to determine the target of the dog's aggression.

Another important step in diagnosis requires looking at the components of the animal's behavior while it is acting aggressively. Dogs exhibiting dominance aggression often, but not always, assume a dominant posture, such as an erect or stiff body position, with erect ears and tail, raised hackles, and a direct stare. Depending on the intensity of the aggressive display, there can be snarling, growling, lunging, snapping, and biting. However, a significant number of dogs with dominance aggression do not exhibit this classical dominance posture and instead, some may exhibit a fear posture or, more commonly, a posture that includes varying degrees of both dominance and fear.

Finally, the veterinarian will consider the dog's age, sex, and breed, as certain dogs will have a greater tendency to exhibit aggressive behavior.

Prognosis: Dominance aggression is rarely, if ever, completely eliminated. Optimal improvement is achieved when a veterinarian who is knowledgeable and experienced in behavioral problems develops an individualized management program. In many cases, the severity of aggressive behavior can be reduced. However, euthanasia may be considered if the animal's problems do not improve and there is a great human safety risk.

Transmission or Cause:

The fact that certain breeds of dogs have a predisposition towards dominance aggression supports the possibility that dominance aggression is to some degree inherited. For this reason, dogs with dominance aggression should not be used for breeding. Environmental experiences also play a role.

Treatment:

Because of the dangerous and complex nature of dominance aggression and the variations between each case, specific treatment of individual cases requires the guidance of a veterinarian with knowledge and experience in the management of canine aggression.

Human safety being the first concern, the veterinarian will first ensure that the animal's behavior is not posing a threat to members of its household. It is particularly dangerous to keep dogs with dominance aggression in homes with children. Due to their small size and their physical movements and actions, young children are potentially more challenging to dominant dogs because they are at eye level and are likely to unintentionally exhibit behaviors that are considered a challenge by the dog.

As much as possible, the circumstances in which the aggression occurs should be avoided in order to prevent the aggressive behavior. For example, if the dog guards its food, it should be fed away from people. Training aids such as head halters and basket muzzles may be necessary to control the dog and prevent its aggression. Physical punishment is dangerous for both the owner and the dog since dogs with dominance aggression become more aggressive in response to punishment.

An important option to consider is neutering. Castration has approximately a 50 percent probability of reducing aggression in intact male dogs. Conversely, there is evidence that spaying intact female dogs that are exhibiting signs of dominance aggression will increase the aggression.

Although obedience training alone will not treat dominance aggression, trainers can help develop behavioral "tools" that can be used in conjunction with specific behavior modification programs. These programs, such as the "Nothing in Life is Free" approach, which requires the dog to defer to the owner by obeying commands before receiving attention, food, or affection, frequently are used to modify the dog's role in the household. Desensitization programs to reduce the dog's reaction to triggers for aggression are often helpful. Both the family and the animal should learn commands such as "sit-stay" or "down-stay" that can help control a dog's behavior in situations in which aggression is likely to occur.

A behavioral specialist may recommend changes in the way the family interacts with the dog to change the dog's perception of its status within the household. Lavish attention and coddling should be permanently withdrawn. In fact, temporarily withdrawing all attention from the dog except for the necessities of life will help "set the stage" for behavior modification. Changes in the dog's feeding routine, exercise schedule, and sleeping or resting sites may have to be made as well.

Finally, drugs that increase the availability of a neurotransmitter called serotonin, as well as other medications that facilitate impulse control, may be recommended for severe cases.

Prevention:
Well-informed selection of a dog may help reduce the likelihood of obtaining an animal that will exhibit dominance aggression. Reliable information should be sought about the breed that is being considered. If possible, information should be obtained on the temperament of both parents and of their previous offspring. Obedience training is recommended because it will help establish a basis of communication between the owner and the dog. Life-long use of a non-confrontational behavior modification program such as "Nothing in Life is Free" can help define the dog's role in the family by requiring the animal to defer to the family members. Mild or subtle signs of aggression should be addressed as soon as they develop. Unfortunately, some dogs will exhibit dominance aggression despite taking these precautions.