Most agression(no matter what type of agression) comes from the fact that the dog has learned to handle a sitiuation by displaying agression. I see a dog I don't like: I growl, bark, lunge and the dog goes away. I see a human coming to me, I bark, snap, lunge: the human goes away. It is a natural responce to display agression. BUT when, for some reason this display of agression does not have the effect the dog wants(the dog does not go away, or the human does not go away) the dog has two options. Either to go away himself or to attack. In our world it is usually impossible for the dog to retreat himself, because they are on lead, or the human does not understand his warning, causing exexaggerated responces. Many dogs are not properly socialized, so they are not very good in "speaking" dog. For example: puppy comes running straight up to a grown dog and jumps in his face. The responce of this grown dog wil be to tell the puppy off, by turning away it's face, raising a lip, growling. The proper behaviour of the pup should be to back off, but since the pup has been with only humans he does not. Leaving the adult dog no choice to apply a nosebite(which is usually not a real bite) and to put the pup on his back. Now the owner of the adult dog steps in and repremands the dog for doing this. The dog learns that warning firmly(which he was doing) is not the way to go. This COULD result in the adult dog becomming agressive towards puppies. Seemingly out of nowhere he will attack a pup. Actually he is doing what he has been tought to do. He has been tought to skip his warning signals, leaving him with no means of telling the pup to back off. So how else can he tell the pup to back off, then with an actual bite? There are numerous examples of this in every kind of agression. What we, humans, forget, is that this is the way the dog communicates. But we find it unwanted behaviour, when a dog growls, so we correct it. Most agression is caused by us, not all. Then, there is also the matter of hierarchie. Natural for dogs, who are pack animals. When dogs live in a pack, they will defend their pack. To our housedogs our family is our pack. They will also defend their territory. What is our dogs territory? Just our house and yard? NO. Most people have a route when they go on walks. One they take every day. Our dogs mark this route. To say they were there and that this is theirs! What COULD happen? Another dog entered their territory and must be chased off!!! He could be a threat to the pack. So he will be attacked. We want our dogs to get along with EVERY dog they meet, something which is very unnatural to them. Now I don't say you should be the PACKLEADER as some trainers say. But it only takes a slight oversight or wrong correction to cause a dog to become excessive in his reaction. Possesion agression works in the same way. In a pack a dog has to guard his food, or it will be taken away by another, stronger dog or a dog higher in rank. So if a dog growls because you want to take away his toy/food, it is up to us to teach him, that he should accept the fact that you take it away. All this agression CAN be cured, but it might take a whole lot of time and work. The examples above are what COULD happen. They are just a few of many facts that could result in agression. I do call my dog agressive. Dog agressive. But in fact he is not. He has learned to fence off other dogs by attacking. Whether that was caused by me or by others or by the fact he has been in pain. Now my dog has taken this a step further and went excessive, by wanting to fight almost every MALE dog he sees and even trying to kill a dog(kill- shake). Now it is up to me to take charge and teach him, this is not acceptable. In comparison there a very few dogs that are really agressive because of the way they are "build" When there is something wrong in the brain. BUT they are there and this is absolutely uncurable. You can train these dogs to be better behaved, but it will never go away. Depending on how severe they are, sometimes it is better to put them to sleep. NO I am not saying that every agrassive dog should be put to sleep, only the ones that have been proven to be uncurable. Because these dogs simply can't function in our society. So maybe I don't agree with you as much as I first said, Tigerlily. I understand and feel just about the same as you do. But I believe that most agression is caused by the world our dogs live in. Whether that was caused before or after our dogs came to live with our family. Caused by us, other dogs, other humans. I have been pondering about this for a while now. Since I do understand the way you think. I have been thinking about how to explain, how I see a dog and his behaviour. Maybe, with this post I have been contradicting myself, but it is how I feel and how I see agression.