Aggression is the most common and most serious behaviour problem in dogs. It’s also the number-one reason why owners seek professional help from behaviourists, trainers and veterinarians.

The term “aggression” refers to a wide variety of behaviours that occur for a multitude of reasons in various circumstances. Virtually all wild animals are aggressive when guarding their territories, defending their offspring and protecting themselves. Species that live in groups, including people and dogs, also use aggression and the threat of aggression to keep the peace and to negotiate social interactions.

To say that a dog is “aggressive” can mean a whole host of things. Aggression encompasses a range of behaviours that usually begin with warnings and can culminate in an attack. Dogs may abort their efforts at any point during an aggressive encounter. A dog that shows aggression to people usually exhibits some part of the following sequence of increasingly intense behaviours:

  • Becoming very still and rigid
  • Guttural bark that sounds threatening
  • Lunging forward or charging at the person with no contact
  • Mouthing, as though to move or control the person, without applying significant pressure
  • “Muzzle punch” (the dog literally punches the person with her nose)
  • Growl
  • Showing teeth
  • Snarl (a combination of growling and showing teeth)
  • Snap
  • Quick nip that leaves no mark
  • A quick bite that tears the skin
  • Bite with enough pressure to cause a bruise
  • Bite that causes puncture wounds
  • Repeated bites in rapid succession
  • Bite and shake

Dogs don’t always follow this sequence, and they often do several of the behaviours above simultaneously. Many times, owners don’t recognize the warning signs before a bite, so they perceive their dogs as suddenly flying off the handle. However, that’s rarely the case. It can be just milliseconds between a warning and a bite, but dogs rarely bite without giving some type of warning beforehand.

If your dog has been aggressive in the past or you suspect she could become aggressive, take time to evaluate the situations that have upset her. Who bore the brunt of her aggression? When and where did it happen? What else was going on at the time? What had just happened or was about to happen to your dog? What seemed to stop her aggression? Learning the answers to these questions can clarify the circumstances that trigger your dog’s aggressive reaction and provide insight into the reasons for her behaviour. You need an accurate diagnosis before you can hope to help your dog.

Aggressive behaviour problems in dogs can be classified in different ways. A beneficial scheme for understanding why your dog is aggressive is based on the function or purpose of the aggression. If you think of aggression this way, you can determine what motivates your dog to behave aggressively and identify what she hopes to gain from her behaviour.

  • Territorial Aggression
  • Protective Aggression
  • Possessive Aggression
  • Fear Aggression
  • Defensive Aggression
  • Social Aggression
  • Frustration-Elicited Aggression
  • Redirected Aggression
  • Pain-Elicited Aggression
  • Sex-Related Aggression
  • Predatory Aggression

 

If you’re deciding whether to live with and treat your aggressive dog, there are several factors to consider because you, as the owner, are ultimately responsible for your dog’s behaviour. These factors involve the level of risk in living with your dog and the likelihood of changing her behaviour:

 

  • Size. Regardless of other factors, large dogs are more frightening and can inflict more damage than small dogs.
  • Age. Young dogs with an aggression problem are believed to be more malleable and easier to treat than older dogs.
  • Bite history. Dogs who have already bitten are a known risk and an insurance liability.
  • Severity. Dogs who stop their aggression at showing teeth, growling or snapping are significantly safer to live and work with than dogs who bite. Likewise, dogs who have delivered minor bruises, scratches and small punctures are less risky than dogs who have inflicted serious wounds.
  • Predictability. Dogs at the highest risk of being euthanized for aggression are those who give little or no warning before they bite and who are inconsistently, unpredictably aggressive. Dogs who give warning before they bite allow people and other animals time to retreat and avoid getting hurt. As counterintuitive as it might seem, it’s easier to live with a dog who always reacts aggressively when, for instance, every time you push him off the bed than a dog who does so only sporadically.
  • Targets. How often your dog is exposed to the targets of her aggression can affect how easy it is to manage and resolve her behaviour. A dog who’s aggressive to strangers is relatively easy to control if you live in a rural environment with a securely fenced yard. A dog who’s aggressive to children can be managed if her owners are childless and have no friends or relatives with children. A dog who is aggressive to unfamiliar dogs poses little difficulty for owners who dislike dog parks and prefer to exercise their dog on isolated hiking trails. In contrast, living with a dog who has recurring ear infections and bites family members when they try to medicate her can be stressful and unpleasant.
  • Triggers. Are the circumstances that prompt your dog to behave aggressively easy or impossible to avoid? If your dog only guards her food while she’s eating, the solution is straightforward: Keep away from her while she’s eating. If no one can safely enter the kitchen when your dog’s there because she guards her empty food bowl in the cupboard, that’s another story. If your dog bites any stranger within reach, she’s a lot more dangerous than a dog who bites strangers only if they try to kiss her.
  • Ease of motivating your dog. The final consideration is how easy it is to motivate your dog during retraining. The safest and most effective way to treat an aggression problem is to implement behaviour modification. Modifying a dog’s behaviour involves rewarding her for good behaviour—so you’ll likely be more successful if your dog enjoys praise, treats and toys. Dogs who aren’t particularly motivated by the usual rewards can be especially challenging to work with.

 

Some aggressive dogs behave the way they do because of a medical condition or complication. In addition to acute painful conditions, dogs with orthopedic problems, thyroid abnormality, adrenal dysfunction, cognitive dysfunction, seizure disorders and sensory deficits can exhibit changes in irritability and aggression. Older dogs can suffer confusion and insecurity, which may prompt aggressive behaviour. Certain medications can alter mood and affect your dog’s susceptibility to aggression. Even diet has been implicated as a potential contributing factor. If your dog has an aggression problem, it’s crucial to take her to a veterinarian, before you do anything else, to rule out medical issues that could cause or worsen her behaviour. If the veterinarian discovers a medical problem, you’ll need to work closely with her to give your dog the best chance at improving.

Aggression can be a dangerous behaviour problem. It’s complex to diagnose and can be tricky to treat. Even highly experienced professionals get bitten from time to time, so living with and treating an aggressive dog is inherently risky. At Total Canine, we can develop a treatment plan customised to your dog’s temperament and your family’s unique situation, and we can coach you through its implementation. We monitor your dog’s progress and make modifications to the plan as required.

Owners of aggressive dogs often ask whether they can ever be sure that their dog is “cured.” Taking into account the behaviour modification techniques that affect aggression, our current understanding is that the incidence and frequency of most types of aggression can be reduced and sometimes eliminated. However, there’s no guarantee that an aggressive dog can be completely cured. In many cases, the only solution is to manage the problem by limiting a dog’s exposure to the situations, people or things that trigger her aggression. There’s always a risk when dealing with an aggressive dog. Owners are responsible for their dogs’ behaviour and must take precautions to ensure that no one’s harmed. Even if a dog has been well behaved for years, it’s not possible to predict when all the necessary circumstances might come together to create “the perfect storm” that triggers her aggression. Dogs who have a history of resorting to aggression as a way of dealing with stressful situations can fall back on that strategy. Owners of aggressive dogs should always be aware that there is a possibility of a reoccurrence and always be on the lookout for potential triggers for aggressive behaviour.