Aggression in dogs


Ratification Date: 15 Feb 2008

Position statement

Aggression is a part of the normal behavioural repertoire of all dogs. People decide whether the intensity and frequency of the aggression and the situations in which it occurs are acceptable. Opinions may differ widely about even a single incident.


As a social species, dogs use an extensive range of signals in their attempts to communicate with other animals, including humans. Aggressive signals are used to protect resources valuable to the dog, such as itself, food, offspring, other animals, people and territory. Because aggressive physical encounters have a potential cost to the dog, dogs usually try to avoid such interactions.

However, if the perceived threat continues and the dog cannot avoid it, the intensity of the aggressive display may escalate and possibly result in a physical encounter. Once they have achieved their objective, most dogs will cease the aggressive interaction.

A few dogs, particularly some members of breeds originally selected for fighting, may fail to show precursors to such an aggressive encounter. They may also fail to stop their aggressive behaviour when the victim shows deference. Dogs of these breeds, and larger breeds in general, possess a body and jaw strength capable of inflicting severe injuries. Such dogs require greater vigilance from their handlers, and may need specific training and other control measures to reduce the chances of aggression. Although the physical characteristics of smaller breeds reduce their capacity to inflict severe injury, some individuals in this group can still pose a serious risk.

Aggression itself is not inherited. However, propensities to be reactive and aggressive are genetically transmitted. The propensity to be reactive is also greater in entire male dogs and in entire female dogs at about the time of oestrus. The threshold for aggression may be reduced when a dog is experiencing pain, discomfort, irritability, anxiety or frustration. If dogs learn that the use of aggression brings about a favourable outcome for them, they are more likely to use this strategy again.

Dogs displaying aggression to other dogs, or to another species, do not necessarily show aggression towards people. However, each dog should be individually assessed to identify the factors contributing towards and triggering the aggressive episodes.

The danger to the community of any dog depends on a number of factors; the size and temperament of the dog is only one of these factors. Other important issues are the dog’s health, the carer’s management strategies (on and off their property), the dog’s level of training, and the owner’s ability to predict their dog’s behaviour and manage it effectively to reduce the chances of an aggressive episode.

Date of ratification by AVA Board 15 February 2008