Combining owners in denial or making excuses for their dogs’ behaviour with our inability to read the signals our dogs are sending all too often ends in an aggressive dog ultimately actually attacking and potentially seriously injuring someone/another dog.

I’d like to point out here that most attacks on people are not, as you would suspect, to strangers, but to family, friends, neighbours and other people owners know. What’s more, overcrowding in cities and large towns means more attacks happen in these environments than in agricultural and other rural areas.

The saddest truth of all this is that in many cases, the victims are children. So many people believe that young children’s need for facial reconstructive surgery is mostly the result of car/other accidents. It is not. It is predominantly the result of dog bites.

Dealing with your dog’s aggression as quickly and effectively as possible is therefore imperative if you hope to prevent potential tragedy. To effectively modify your dog’s behaviour and turn him from a constant source of stress and worry into a lovable, safe companion everyone can enjoy being around, you need the help of an experienced behaviourist.

Why a Behaviourist?

The reason you need a behaviourist if your dog is aggressive towards other dogs or humans is simple: aggression – both towards dogs and humans – can be related to an endless list of potential factors, including among many others, diet, fear or dominance; illness, pain or territorial matters; aversion, one-incident reactions or a genetic disposition to be aggressive; learned behaviour, guarding or hormonal causes. The incredible complexity of potential triggers involved in what caused your dog’s aggression to begin with makes it necessary to take a multitude of factors into account before setting a suitable, workable program to resolve the problem.

What’s more, there are more than 50 potential medical reasons for a dog becoming aggressive. Ruling these possible causes out before all else is therefore highly recommended, especially in cases where the aggression came on suddenly and is truly out of character for your dog.

To make matters more complicated still, your choice of dog can also affect your pet’s likelihood to be aggressive or bite. Guarding breeds predominantly guard; retrieving breeds predominantly retrieve and herding breeds predominantly herd. In other words, if you have a dog that was bred as a guard dog, you should not be terribly surprised if guarding is what he does.


Remedial Classes

Once medical causes have been ruled out, a well-versed and experienced expert in canine behaviour will work out the type and trigger/s of your dog’s aggression and set a suitable program to modify this behaviour. At this point, remedial training classes may be used to assist with desensitisation to triggers.

Types of Aggression

Inter-dog aggression is a very different, separate behavioural concept to human aggression. What both concepts of aggression have in common is that they:

  • Can be caused by myriads of different factors
  • Present a potential risk to others
  • Cause owners a great deal of stress
  • Must be dealt with as soon as possible

The following paragraphs show some of the most common types of aggression.

Fear Aggression

In my experience, most cases of aggression are based on fear, although we frequently categorise aggressions as Nervous/Fear, Protective, Territorial, Sexual or Predatory aggression. Fear aggression can have many different causes, from a general nervous disposition to having been abused/abandoned at some point (especially in rescue dogs) and anything in-between.

The one thing you should NOT do if you believe your dog is fear-based aggressive is to rush out and get him neutered, because neutering frequently heightens, rather than cures, aggression. That all too common cry: “Oh, just get him neutered, that’ll sort him out” has, as a matter of fact, caused the euthanisation of more dogs than virtually any other comment.

Yes, neutering may help with males that fight with other male dogs that are ‘intact’. It does, however, never help with females and, if the aggression is directed at both male and female dogs (in which case it is usually fear based), generally makes matters considerably worse.

What I’m trying to say here is that you should explore other avenues before rushing out to have your pet neutered – do not follow the advice of armchair experts and even vets, most of which not only have little to no knowledge of canine behaviour, but also have strong financial interests in neutering.

All this said, it is, however, extremely rare indeed for a dog to have only one of the above-mentioned problems – and fear, nervous and dominant aggression linked together is the worst combination possible.

Inter-Dog Aggression at Home

Principally social in context, inter-dog aggression at home (between dogs living in the same house) is rarely driven by hormones, although it does usually (though not necessarily always) start when dogs reach the age of social maturity (between 12 and 24 months). A dog feels challenged by a body block, bump or stare and each dog subsequently reacts to the action/reaction of the other dog. Unless dealt with early, this will eventually escalate into an ‘all-out-war’.

Although these dogs may well have been the very best of friends – even siblings – a few weeks before ‘trouble started brewing’, they can then easily end up seriously hating each other. I have seen some households perform almost military operations to ensure their pets never meet.

When things have reached this stage, unless you get help from someone who understand canine behaviour and knows how to work with aggressions of these types, you may ultimately end up having to rehome or even euthanise one of them. Early intervention is the key to preventing this.

If your dogs start fighting at the mere sight of each other, their aggression is usually caused by fear and their response is one of protection aggression (and, in some cases, classic lead aggression). One inter-dog aggression characteristic is that aggressive intentions are almost never displayed towards other animals – a dog with this kind of aggression may well live perfectly amicable with cats, horses and/or other pets/animals.

Protective Aggression

Sudden movements (like, for example, someone suddenly getting up) can trigger aggressive responses in dogs with protection aggression. This behaviour is frequently inhibited by dogs in the absence of their owners or the child, person or dog they feel they must protect (no-one to protect). In strange places or places with lots of people and/or dogs (like a dog show, for example), they may also be non-reactive.

Under these circumstances, a dog may not display this behaviour because he is flooded with all kinds of potential threats and cannot identify specific threats.

Some dogs protect animals or people they consider vulnerable. In many cases, these dogs were never aggressive until a new baby or a puppy was introduced into their home. Often, they are fine while indoors, but become protective towards strangers and/or other dogs when outdoors – or vice versa.

Both male and female dogs may display this kind of aggression, which usually starts when they reach mental and social maturity. At which age this occurs depends on their breed, but on average, it happens between the age of 12 and 36 months. The larger the breed, the older the dog is before he/she displays this kind of behaviour, and the trend is rarely, if ever, seen in puppies.

Barking is generally considered a protective aggression sign (like a dog barking when you pass ‘his’ garden’, for instance). In contrast, signs of dominance aggression typically involve staring, snarling, growling and biting.

Hormonal Aggression

Occuring overwhelmingly (90 per cent of cases) in male dogs, hormonal aggression first becomes obvious when the dog reaches social maturity (between 12 and 24 months), may run in families and worsens with punishment.

This is the type of aggression that is looked for during the 8-week test for puppies. If it can be successfully identified at this age, early intervention becomes necessary to save the dog. Unfortunately, dominance aggression cannot be identified in all dogs at 8 weeks.

Territorial Aggression

Most dogs display territorial aggression signs to some extent: they may bark when someone knocks on the door, they may protect the car, and/or they may bark at people passing them/their home on the pavement. All social animals will exhibit some territorial/protective aggression, and dogs are no exception.

Increased by fences, which enable dogs to continually “patrol and protect”, this behaviour can also be made worse if a dog is chained up or enclosed by, for instance, an electric fence. Tolerating “door greeting” abnormalities – i.e. holding your dog back (straining at his collar and possibly growling and barking…) when greeting people at your door – can also make this behaviour worse.

Dominance Aggression

Unlike object or food aggression, which are essentially all about possessing something, dominance aggression is considered a control or challenge (will my dog growl or get off the couch?) concept. More common among dogs with male owners (who often like the idea of “big, tough dogs”), a dominance aggression diagnosis may be more likely in some breeds than in others.

The worst cases of dominance aggression I have over the years dealt with, however, were in Chihuahuas, Shih Tzus and Toy Poodles. The problem here is that in dogs of this size, the behaviour is much more likely to be tolerated and even considered innocent by owners.

There are around 15 ways (including things as simple as making lead corrections, leaning over the dog, pushing on the dog’s rump or staring at him) in which people can exacerbate this kind of aggression.

There are also around 20 signs of a dog intending to get dominant aggressive. Such signs may be a seemingly innocent as, for example, jumping into laps, leaning against people or standing on their feet; standing in front of people in doorways, and “talking back” (always ‘getting the last word in” with a grumble, bark or growl).

It totally eludes me why these signs are frequently ignored in smaller breeds. Sure, they may not be able to inflict as much potential damage as, for example, a mastiff or a German Shepherd, but as far as I am concerned, that should by no means be an excuse for aggressive behaviour.

Dominant aggressive dogs are categorised behaviour-wise as dogs who believe they are Alphas (in control of people and always getting things their way) – which is usually a bad prognosis – or dogs that displayed all the signs of dominance aggression and were allowed “to get away with it”:

  1. Although other aggressive behaviour may not necessarily predict dominance aggression, which is about control, dogs with dominance aggression generally also have other types of aggression. A common trait of dominant aggressive dog is (strange as that may seem) that they can also be highly sensitive and can also have anxious or fear aggression. This could almost class these dogs as schizophrenic.


  1. Dogs are very much like teenagers testing their boundaries by starting to talk back – and when their owners allowed them to escalate through several dominance aggression signs (sitting in laps, standing on people, etc.), they think they are in charge.


This class of dog will adjust its behaviour according to individuals and may not be aggressive around an experienced trainer (who is in charge) or not bark at people going by while eating, for example. Here, the dog can inhibit/interrupt his aggressive behaviour, but will react/not react at a time of his/her own choosing. These dogs are, in fact, the easiest to work with, because the can take cues from context and behave appropriately.

Determining precise genetics for this kind of behaviour would, however, be extremely difficult, as behaviour development depends on both genetics and dog-owner situations. If, for example, a dog is genetically predisposed to be dominant aggressive, but is owned by an experienced, good trainer who discouraged him, say from barking at a door, from an early age, he may never exhibit this trait again.

On the other end of the spectrum, if a dog that is less genetically predisposed to dominance aggression is actively encouraged to display this kind of behaviour, the behaviour may ultimately turn into a major problem.

Finally, non-neutered (intact) male dogs are more likely to be dominant aggressive (though only towards other non-neutered dogs) than male dogs that were neutered or females that were spayed. It is, by the way, most likely for this to be controlled by androgen, as females who display aggression before puberty often become more aggressive when spayed.


The roots of dogs’ aggression problems often go way back to early games/contact with both people and other dogs. Early socialisation (which should begin well before the age of 16 weeks) with other puppies and people is therefore an absolute must.

There are critical periods during which puppies learn, with period from birth to 16 months being the most important. Communication with other dogs is not learned from older dogs, but from pups of the same/similar age. During this time (birth to the age of 16 months), a puppy should be handled by a minimum of 100 different people of all ages, from young children to older adults.

Giving owners control over each one of their dogs, taking responsibility & controlling games should help with this kind of unacceptable behaviour both in the short and long run.

Is Your Dog Aggressive?

Specialising in canine behaviour, I have over the years helped thousands of dogs overcome aggression issues, with fear and protective aggression being the most common among the cases I am asked to treat. If you have an aggressive dog, don’t wait until something terrible happens – call me today and I will help your beloved furry friend let go of his aggression and become the enjoyable companion you always wanted.