Aggression problems are fairly common in dogs. The biggest issue is that there are different categories of aggression and it is not a “one solution treats all” sort of thing.
There are volumes of studies and treatments that have been compiled over the years. I am going to try to give a general guideline for various situations that we face with our family dogs.
Possession aggression - this is when the dog has physical possession of something and does not want or does not allow anyone to get close to it without perhaps growling or even snapping. The list of common items is endless and varied. This list can include food, treats, chew items, their bed, toys, Kleenex, a string, people and owners, etc
Territorial aggression - this can include a room, their yard, their house, etc.
Fear aggression- can involve people, animals, novel objects are to name only a few and can be expressed by any behavior from cowering to lunging and biting.
There are different specific treatments for each category and vary depending upon intensity and duration of behavior but all involve some common strategies.
1. The dog invariably needs more structure put in place in their day to day life.
2. Items that the dog guards needs to be removed (at least for present time) and replaced with lower value alternatives if possible.
3. A program of obedience put in place to reinforce leadership the correct way (hitting, screaming at the dog will not solve the problem.)
4. Food aggression needs to have its own specific program.
5. Fear aggression involving strangers needs to be addressed with an individualized program to desensitize the dog to what it is afraid of.
Most important is that the dog learns what the new rules are, be able to understand them clearly, and be rewarded in various ways to reinforce improvements in behavior. All household members must be on the same page and be consistent.
The dog must understand that the house, gates, yard, etc. belong to the owners and not him and therefore there is no need nor permission to guard them.
With mild cases of any of the above, a lesson or two with guidance from a professional experienced with such issues may be all that is needed. But with more moderate to severe behavior involving biting and threatening behavior in this area, some ongoing guidance from a professional is called for.
There are so many suggestions for solving these issues that are found in the Internet. It is definitely a “buyer beware “ situation to make sure the dog’s behavior is addressed appropriately and not made worse in the long term