Aggression is the most common behavior problem presented to veterinary behaviorists, followed by anxiety-related disorders such as separation anxiety and phobias. Traditionally, dominance aggression has most often been diagnosed, especially when evaluating owner-directed aggression. As a result of the label “dominance” being applied in these cases, owners were often directed to establish themselves as higher ranking over the dog through the use of a variety of physical means (e.g. punishment, alpha rolls, leash hangs, pinch and shock collars). Escalation of aggressive responses often followed this approach.
By examining the situations in which the aggression occurs, observing the body posture exhibited by the dog and evaluating the early history of the behaviors, it becomes evident that not all aggression is related to a question of dominance hierarchy. In many—if not most—of these cases a definite fear component seems to be the driving force behind the aggressive displays.
Normal role of canine aggression and its misdirection
Aggression is a normal canine behavior when displayed in the proper context. As a tool, aggression is used by dogs for a variety of purposes such as food acquisition, defense of resources (food, territory, mating access), establishment of pack hierarchy, and self defense when threatened. In addition, submissive displays (averting stares, exposure of the underbelly, urination and retreat) are often used when a dog is presented with an overwhelming threat. If these signals are not recognized, a subordinate individual may be forced to rely on aggression (growling, barking, snarling or biting) as a last resort.
When examining these behaviors in the context of human-canine interactions, several factors must be considered. First, do dogs and humans communicate in the same manner? While both are social species, methods of exchanging information differ. Often submissive signals are missed by observers not familiar with canine body language. As a result, dogs may be put in a position to use aggression when more subtle signals of submission are missed. Over time, learning can occur such that some dogs will totally abandon submissive cues and instead more quickly elect to use more offensive strategies to alleviate perceived threats.
Second, when punishment is used by people as a means of exerting dominance, fearful dogs may be forced to respond aggressively while more confident animals may see the use of punishment as an incentive to raise the bar by showing higher and higher degrees of aggression in response to ever increasing levels of punishment. In addition, punishment is often applied inconsistently, creating increased anxiety in the fearful animal. Not knowing whether to expect reward or punishment, the dog experiences conflicting emotions, resulting in a lower threshold of reactivity and an increased chance the dog will resort to the use of aggression.
It also appears that fear can be highly inherited so that fearful, anxious or timid parents can produce a higher number of similarly behaved puppies in a litter. Combine this genetic component with the previously described communication breakdown, and the true meaning of nature and nurture can be seen. In addition, failure to positively socialize puppies during the sensitive period (up to 14 weeks of age) results in the genetic prophecy of fearful behavior being fulfilled.
The principles of reinforcement and conditioning apply to the dog’s use of aggression. You need to know the situation in which the aggression is occurring and the past history of aggressive behavior in order to make a proper diagnosis. Aggression is not static. Constant interaction of genetics and environmental influences can determine behavior at any one point in time.
Diagnosing fear-based aggression
A dog’s body posture at the time surrounding the aggressive episode can be most valuable in determining the cause. Typical signs of fear include:
- Dropped or tucked tail
- Ears laid back
- Dorsal piloerection (evidence of arousal and nonspecific for fear)
- Weight positioned over hindlimbs with the head and neck lowered
- Dorsal gaze or sideway glance at target
- Autonomic responses—urination, defecation, anal sac expression
- Lip retraction (vertical)
The above signs may be the early presentation in a younger dog. Over time, the body language may suggest a more confident dog as it learns to deal with its fear and anxiety by adopting a more offensive strategy:
- Raised tail
- Ears forward
- Weight shifted forward with head raised
- Staring directly at target
- Lunging at or chasing target
In a fearful animal, the target is often an unfamiliar person but can be a very familiar person when conflict exists (see “Diagnosing conflict aggression” below). Sometimes an initially offensive aggressive dog can revert to a more defensive body posture if the threat does not retreat or is sudden and overwhelming.
The situation often also helps determine etiology. A typical presentation in which fear is induced and has the potential to result in aggression includes:
- Approach from a stranger while on a leash walk (the leash can transmit owner anxiety, prevents escape by the dog, and also prevents canine-specific communication in cases of interdog aggression).
- A person reaching toward a dog (the dog may bite the person’s hand)
- A person turning his or her back to the dog (a dog may bite the person’s backside or caudal thighs or feet; common with herding breeds)
- Secondary to punishment by strangers or owners
- Strangers entering the home or moving suddenly
- The presence of young, mobile, active children since unpredictability breeds anxiety in dogs and can cause biting to prevent movement.
Abuse can cause fearful behavior but it is displayed as fear toward a specific trigger as opposed to more generalized responses.
Diagnosing conflict aggression
Conflict aggression, which is often owner-directed, is also frequently diagnosed as dominance aggression. It occurs when dogs are put in confrontational situations or when they cannot predict what will happen during an interaction. For example, owners may use punishment inappropriately, attempt to create an owner-canine dominance structure in the household or be inconsistent in their interactions with their dogs.
Affected dogs often show submissive postures and ambivalent body language (wagging their tails while growling) and may show “remorse” after aggression. These dogs learn to use aggression to get out of uncomfortable situations and are reinforced for the behavior.
If you’ve determined that fear-based or conflict aggression is indeed at play in one of your patients, click here for Dr. Ciribassi’s guidance on treatment, which involves removing stimuli, counterconditioning, desensitization and medication.