Aggression in dogs

We hear all the time dogs being described as 'aggressive'.  

However, understanding the type of aggression is very important in how to treat or deal with it.  Understanding a dog's body language is vital in any form of training or behaviour therapy or simply how your dog is feeling.

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Entire books have been written on the subject of aggression.  This page is a simple look at 2 forms of aggression and the body language that is displayed.

The picture to the left illustrates well all the signs of fear-based aggression.  To the right, is the signs of dominant aggression.

The overall position of the body is always my first clue.  A dog will generally crouch or lower its body.  This is a sign that ‘I’m really no threat’ and is an attempt to make itself smaller.  Although the picture doesn’t show it another sign of ‘I’m really no threat’ is that the dog will often turn its head away very slightly and (most of the time) avoid eye contact.  However, the other signs show ‘but I will attack if pushed’.

Another sign of aggression is the raised hackles.  In the picture above, it is most certainly caused by aggression (in this case fear) but raised heckles don’t always mean aggression.  When a dog raises its hackles it's called ‘piloerection’.  This is similar to our hair standing up on the back of our necks and is an involuntary action that can be excitement, stimulation, arousal, being startled or interest.  Lots of dogs at the daycare centre do it when first meeting and most of the time is not a sign of aggression but more of excitement and interest.

The position of the tail in the picture above is a clear sign of fear. Research generally suggests that the dog is trying to make itself as small (and un-threatening) as possible and some also think it is an attempt to hide or protect genitals. The attempt to make itself smaller also relates to the position of the ears.  When scared and intimidated, a dog will pull its ears back and down.

The ‘snarl’ or rather the combination of a wrinkled nose and slightly open mouth showing teeth, is similar in both fear and dominant aggression.  The slight difference is the shape of the open mouth.  The fear-aggressive dog will pull back the corners of its mouth and the dominant display is a more forward, C-shaped mouth.  I’m afraid I really couldn’t find a reason why this difference occurs.  Maybe one mouth shape is easier to bite (if needed), maybe just a subtle difference that changes the face and head shape to give a true indication of an intention to another dog. The fact is the difference exists and should be noted.

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When comparing the two pictures, it could easily be translated that the fear-aggressive stance is a ‘retreating’ stance.  Lowering the body, becoming less intimidating but still with the attitude of ‘I don’t want to bite but will if pushed’.  It can easily be seen that the dominant aggressive stance is a lot more like ‘I’m in charge and I’m ready’.  Its important to understand the type of aggression that is being displayed in order to find the causes of this behaviour.