Q: What is dog aggression?

Dog aggression is an overloaded word. It can mean anything from staring, jumping, showing teeth, lunging, growling, barking, or biting.

Usually, aggression is used to describe dogs that overact to a stimuli (e.g. another dog, a stranger, food).

All behaviour is dependent on the influences of inheritance, learning and the environment. Aggression may be normal or abnormal depending on the context. It is important for dog owners to be aware that aggression can be caused by underlying fear and anxiety.

My dog is being aggressive – why?

Q: What are the types of dog aggression?

Several forms of aggression have been recognised in dogs including:

Fear-motivated aggression is a defensive reaction and occurs when a dog believes he is in danger of being harmed. Remember that it’s your dog’s perception of the situation, not your actual intent, which determines your dog’s response. The dog may bark, growl, snarl while backing up in a response to people, or other animals. The dog shows fearful body posture, with its tail and ears down. The dog may bite from behind and run away.

For example, you may raise your arm to throw a ball, but your dog may bite you because he believes he’s protecting himself from being hit. A dog may also be fearfully aggressive when approached by other dogs.

Protective, territorial, and possessive aggression are all very similar, and involve the defense of valuable resources. Territorial aggression is usually associated with defense of property, and that “territory” may extend well past the boundaries of your yard.

For example, if you regularly walk your dog around the neighbourhood and allow him to urine-mark, he may think his territory includes the entire block. Protective aggression usually refers to aggression directed toward people or animals whom a dog perceives as threats to his family, or pack, property by barking, growling, snarling, biting. Dogs become possessively aggressive when defending their food, toys, or other valued objects, including items as peculiar as tissues stolen from the trash. 

Redirected aggression is a relatively common type of aggression but one that is often misunderstood by pet owners. If a dog is somehow provoked by a person or animal he is unable to attack, he may redirect this aggression onto someone else. For example, two family dogs may become excited, and bark and growl in response to another dog passing through the front yard; or two dogs confined behind a fence may turn and attack each other because they can’t attack an intruder.

Predatory aggression – the dog silently stalks small animals, birds. It may also stalk infants and drooling is a common sign. Predation is usually considered to be a unique kind of aggressive behaviour because it’s motivated by the intent to obtain food, and not primarily by the intent to harm or intimidate.

Fear aggression – the dog may bark, growl, snarl while backing up in a response to people, or other animals. The dog shows fearful body posture, with its tail and ears down. The dog may bite from behind and run way. It looks for escape routes when cornered.

Pain aggression – usually in response to being manipulated, bumped or touched.

Sibling rivalry aggression – dogs living in the same household may not get along.

Sexually-related aggression – usually occurs between intact male dogs.

Why Dogs Get Aggressive Over Food and Toys

Individual variation

The likelihood of a dog to show aggressive behaviour in any particular situation varies markedly from dog to dog. Some dogs tend to respond aggressively with very little stimulation. Others may be subjected to all kinds of threatening stimuli and events and yet never attempt to bite.

The difference in the threshold prompting aggressive behaviour is influenced by both environmental and genetic factors. If this threshold is low, a dog will be more likely to bite. Raising the threshold makes a dog less likely to respond aggressively. This threshold can be raised using behaviour modification techniques, but the potential for change is influenced by a dog’s gender, age, breed, general temperament, and the way in which the behaviour modification techniques are chosen and implemented.

Because working with aggressive dogs can be potentially dangerous, behaviour modification techniques should only be attempted by, or under the guidance of, an experienced animal behaviour professional who understands animal learning theory and behaviour.  

Q: How can aggression be treated?
  • First, check with your veterinarian to rule out medical causes for the aggressive behaviour.
  • Seek professional advice. An aggression problem will not go away by itself. Working with aggression problems requires in-home help from an animal behaviour specialist.
  • Take precautions. Your first priority is to keep people and other animals safe. Supervise, confine, and/or restrict your dog’s activities until you can obtain professional guidance. You are liable for your dog’s behaviour. If you must take your dog out in public, consider a cage-type muzzle as a temporary precaution, and remember that some dogs are clever enough to get a muzzle off.
  • Avoid exposing your dog to situations where he is more likely to show aggression. You may need to keep him confined to a safe room and limit his contact with visitors or other people.
  • If your dog is possessive of toys or treats, or territorial in certain locations, prevent access and you’ll prevent the problem. In an emergency, bribe him with something better than what he has. For example, if he steals your shoe, trade him the shoe for a piece of chicken.
  • Spey or neuter your dog. Intact dogs are more likely to display dominance, territorial, and protective aggressive behaviour.

Treatment for aggression often involves behavioural modification techniques. These techniques use positive reinforcement as the basis – reward ‘good’ behaviour and avoid reinforcing ‘unwanted’ behaviour. Treatment for aggression generally does not involve the owner ‘punishing’, using aversion therapy or being aggressive towards the dog as this is likely to make the dog’s aggressive behaviour worse.

For example, a fearful dog being walked on leash may become anxious upon seeing an unfamiliar dog at a distance, and react by becoming more aggressive as it approaches. The fact that the dog is constrained to a leash may increase its stress levels, as the dog perceives its escape options to be limited. If the owner chooses to scold or punish the dog at this stage, it could cause the dog to associate unfamiliar people or dogs with both punishment and fear, thereby reinforcing the anxiety-related aggression and making it worse.