What makes a dog aggressive?

Lots of dog owners would prefer a pet that was mild mannered, and behaved itself around other dogs and household pets. However, aggression is a funny old thing, and a calm, submissive dog may turn in to a whirlwind of teeth and claws at the drop of a hat. If you have an aggressive dog, the key to managing it is to understand why he gets lairy.

Many dog behaviourists use two things to assess the extent of aggression – bite threshold and bite inhibition.

Bite threshold is an assessment of how quickly your dog becomes aggressive. Does it take a particular set of circumstances, or does he go off like a bottle of pop as soon as he sees another dog? Bite inhibition, however, asks how hard your pet bites. Does he just nip, or does he attempt to remove a limb?

Many behaviourists would argue that inhibition is more important than threshold; after all, it’s preferable to have a dog that nips often but never injures another rather one that seldom bites but causes severe injury.

A dog can be repeatedly aggressive if aggressive behaviour is rewarded. In this context, a reward would be something like controlling food or a dog toy, or the onset of adrenaline and other ‘feel good’ chemicals coursing through his body after a confrontation.

Fear is a main motivator for aggression. Reasons for fearfulness in a dog may include a neglect to socialise him when younger, a genetic predisposition to it (how many ‘nervous’ breeds can you think of?) or a learned response.

Many owners unintentionally encourage their dog to be aggressive. This may be when they try to calm their pet down with a soothing tone of voice after an aggressive incident, punishing their dog and therefore increasing levels of adrenalin, or chasing the other dog away. The latter reinforces to your pet that strange dogs are to be chased, and he will interpret your behaviour as aggressive.

However, there are other motivators for aggression, such as guarding his resources (which include food and dog toys), prey drive and barrier frustration. In the case of barrier frustration, your dog may just be desperate to interact with other dogs, but is prevented from doing so by a leash or an obstacle. If the dog lacks social skills, this desperation may manifest itself as aggression.

Now that we know what can trigger aggressive behaviour Part 2 of this article will look at ways of correcting it.

Mark James