First, there’s a difference between a dog showing aggressive behavior and a truly aggressive dog. In this case, we’re dealing with a dog that isn’t really aggressive, but which is showing that kind of behavior.
Being pack animals with a leader and followers, dogs like regularity and consistency. They like to know their place in the pack and what’s expected of them. When the pack is balanced and something happens, every dog knows exactly what to do.
Think of it like a bunch of firefighters — when a professional team arrives on the scene, each member knows what their responsibility is. Someone carries the hose, someone hooks up the hydrant and pumper, someone else leads a rescue team into the flaming building if they believe people are in there, and someone directs everyone else.
Now imagine the scene if those firefighters had no assigned roles and no one directing them. It would be chaos. You could easily wind up with a hose rolled out in both directions and attached to nothing, everybody running into a burning building to be a hero when there are actually no people inside, and half a dozen people barking conflicting directions.
That’s no way to run a fire department, and it’s no way to run a pack. Not knowing his position will make a dog very insecure, especially if there is no leader and are no dogs to show him his place. Insecurity makes a dog very anxious, and that can elevate their energy level. Left without any rules, that dog is very likely to become defensive, and every dog’s main defensive weapon is in their mouth.
When a truly aggressive dog bites, it means to kill. When an insecure dog bites, it’s saying, “Please leave me alone” in the only way it knows how. Of course, that dog doesn’t need to be left alone — it needs a pack with a leader and its own clearly defined place within that pack