An unexperienced owner may not be able to determine the difference from looking at the dog. A bite is a bite, a growl is a growl, fight behavior is fight behavior. To a layman, it “looks” the same. However, there are indications such as overall posture, disposition, type of bark, and body language to determine fear (defensive) vs confidence (aggressive).
The differences between AGGRESSION (dog bites out of confidence) and DEFENSE (dog bites out of fear) are in fact significant and mainly happen in the mindset of the dog, or how the dog feels in that moment. The dog biting out of fear is in fight and/or flight mode. If it cannot flee right away, it will fight only to enable itself to flee (flight). A dog with this mindset may say: "I feel cornered, I want no trouble, I just want to make you go away enough so I can escape (flight)". The dog biting with confidence is on the offensive (aggression) and may say: "I am bigger than you, I don't like you, and I'm going to stir it up. I will not move!"
Both scenarios are very real to each dog and based on the dog's temperament and disposition, each dog would fall into one of these two categories in a given scenario. While you may not want a biting dog, regardless as to why your dog is biting, it is in fact important to know the mindset difference when modifying the problem.
A defensive dog likely needs to be behavior modified differently than an aggressive dog. A fearful dog needs to be methodically built up so it gains confidence, thus eliminating its fear causing the defensive display. An aggressive dog needs to be throttled down with structure, rules and relationship building to clearly cement pack order to result in happy and balanced co-existence.
It is rare for a dog to be flat-out aggressive. Within the pet dog environment, easily 97% of bite issues are fear based (due to lack of socialization and deficient amount of confidence building), versus aggression based.
