Dog owners are devastated if they find that others regard their dog as aggressive. Sometimes this dawns on them only when someone with a limited vocabulary shouts "You should keep that b***** thing on a leash". For others the discovery is by more subtle means such as finding that the vet has put a warning notice for other members of staff on their dog's records. Of course the aggression may be directed towards themselves. However a dog is never aggressive for its own sake, there has to be a reason and if we understand those reasons we can prevent and manage the behavior more easily.

Aggression is a term used to describe a pattern of behavior but there is a range of reasons why it may be caused. Collectively the various motivations constitute some 46% of the referral of dogs to members of the Association of Pet Behavior Counsellors by veterinarians.

The Aggressive Dog

There are some common misconceptions about aggressive behavior. It is not often appreciated that its very presence is indicative of the fact that other mechanisms such as signaling by using body language, vocalization or moving to try and avoid conflict have failed. We tend to look at the end result of teeth and spittle and forget that aggressive behavior is symptomatic of a range of chemical processes that take place within the body in response to external events. In ourselves we would describe these processes as emotional states such as fear and frustration. The likelihood of these processes taking place and resulting in aggression is influenced by factors such as genetics, previous learning and health. The fact that these emotional states take place internally means that the labeling of the aggressive behavior we actually observe is unreliable. However we have to have means by which we can communicate our thoughts about the reason for a dog's aggression and so descriptive terms are used.

The most common descriptions of aggressive behavior include fear aggression, anxiety related aggression, and territorial aggression, possessive aggression, food guarding and status related (dominance) aggression. However the dog's emotional state in all these could involve a sensation we would describe as fear. Fear of strangers in the case of territorial aggression, fear that another will take something away in the case of possessive and food guarding behavior and fear of a loss of a resource in status related and jealous behaviors.

A study of fear aggression, as it is more commonly labeled, shows how complicated aggressive behavior is. Fear aggression can be caused by a lack of early socialisation with the species a dog will live with or a noxious experience. Often, however, a dog is predisposed to fearful behavior due to a lack of early life experience but this, and the subsequent development of aggression, does not occur until the dog is subjected to a fear-inducing event. For example a dog may be wary of other dogs because of a lack of socialization opportunities after it left its mother and litter-mates but displays of aggression may not occur until it is attacked by a dog in the park.

When aggressive behavior starts to develop it is often directed at a specific stimulus. In our example the dog may be attacked by a black dog and, initially, it may direct all its aggressive tendencies towards all dogs this color. In time this may generalize to include dogs that are black and white, then dogs of all colors. A similar generalization process can occur with size. If a dog is attacked by small dogs it may display aggressive behavior specifically to dogs of a similar size, but in time its aggression may generalize to include dogs of all sizes.

This does not mean to say that the presence of another dog will trigger aggressive behavior. A response depends on factors such as how close it is and whether or not its behavior appears to be threatening.

Often owners will report that their dog's fear aggression started to develop around the time that it became sexually mature. At one level we can consider that this change takes place because of the neuro chemical changes that take place in the brain at this stage of development. At another level we can look at this as a behavior change that takes place as the dog moves from the juvenile to the adult stage of its development.

For the behavior to develop at all learning opportunities are necessary. If the dog does not have the opportunity to bark at or threaten whatever it is frightened of and witness that it is either taken away from the subject by its owner or the subject moves away, it will not develop the confidence to use aggression as a means of coping. This probably explains why many of the dogs that display very overt fear aggression towards people when they are away from home have had lots of opportunity to display territorial aggression. In territorial situations a dog often has many opportunities to bark at people that either approach the owners’ property or pass it. Each time it displays its threatening behavior it finds that the stimulus it barks at goes away, which increases its confidence in the use of aggression in this situation. Subsequently, the confidence to use aggression as a means of coping generalizes to other situations.

When faced with a worrying situation a dog will typically try and display avoidance behavior. However when avoidance is not possible because the dog is on the leash, in a territorial situation as described above, or otherwise feels that avoidance behavior is not possible, it may display aggression as a means of deterring what it is worried about. When it is on a leash and faced with the presence of strangers it may bark to make them go away. As with the territorial behavior described above the individuals typically go away. Although this is on their own violation from the dog's perspective it appears that they have gone away because of its behavior. As a consequence of this its confidence to display aggressive behavior when it is on a leash may start to increase.

A dog's aggressive behavior towards the people it lives with can develop in much the same way. It may not occur until after maturity, it does not occur to the dog to display it until it has been assaulted, however mildly, for some misdemeanor it has no comprehension of, or comes into conflict or competition with a family member. Having found the behavior effective it may be more inclined to do it again the next time circumstances cause those same emotions of fear or frustration to swell up. The punitive response of the person involved may serve only to heighten the sense of anticipation on subsequent occasions. Initially the aggression may be directed to a specific individual but may generalize to include other, unsuspecting, members of the household.

Although this has been a mere sketch of the of the complexities of aggression it will, hopefully have been enough to point out that, unless caused by a medical problem, every act of aggression shown by a dog has a history we can learn from.

© David Appleby 1998

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Please note that techniques are advised upon in good faith and no liability can be held in the event of damage or injury to persons, property or animals as a result of correct or incorrect implementation of the techniques described.