The truth is that very few of these calls are for, what I would consider, an aggressive dog. My definition of aggression is when a dog bites and then has to be physically removed from the person or dog he is biting. Thats a committed bite. A dog that bites and then withdraws is not aggressive, hes just sending a message. Dont get me wrong, its still a serious issue that needs to be addressed, but were not dealing with a dog that is actively aggressive. By that I mean, hes not a dog seeking out a fight, hes a dog that has be forced (in his mind) into an aggressive action.
One such call I received was from a mother who had a small dog that had "snapped" at her two-year-old daughter. She was very upset because her dog had never done anything like that before. Now, I was being called as a last resort before they gave the dog up. This was not a new dog, this was a dog that they have had for years.
When I got to the home and asked some questions I discovered that the little girl was petting the dog roughly and pulled on his ear. Thats when the dog "snapped" at her. My client didnt like it, but I told her that the dog wasnt to blame, she was. The dog simply told the little girl not to pull his ear. Supervision over the child, teaching her how to interact with the dog is all that is needed to stop this from happening ever again.
Its not always that simple. Especially when a dog bites because of fear or anxiety. Those bites are much more frequent than true aggression cases and requires us to recognize when our dogs are not feeling comfortable about a situation. This also is not the dogs fault.
Puppies almost never show any signs of aggression period. I just got two calls from people saying their young puppy was showing signs of aggression. I told them I would be happy to help them with their issues but that there is no way its aggression. The only thing on a puppys mind is play. 24/7.
Aggression in dogs does exist but its actually fairly rare. All I can say to you is watch the signs your dogs is giving you. No dog ever does anything "out of the blue." Their bodies are always telling us exactly how they are feeling. So, if you see some signs that your dog is asserting himself or has made some unfriendly advances, work on it immediately so you can understand exactly why hes behaving like that and what you need to do to correct it.