How to Stop New Dog on Dog Aggression by Adding Rules and Structure

By: David Codr

Published Date: March 21, 2017

Star (left) is a five-year-old Silver Lab who lives with a Black Lab named Tazy (not pictured) and Shiloh, a six-year-old White Lab. The dog’s guardians were referred to me by Benson Animal Clinic so that we could do some dog behavior modification as Star is now acting aggressively to Tazy; attacking him when inside the house.

I was told that Tazy and Star were good buddies up until recently when Start started to go after Tazy. While Tazy was not starting any of the dog fights, he was not backing down either. Things had gotten so bad that the guardians now have to separate them when inside.

While I thought Star’s dog aggression was exclusively directed at Tazy, I discovered that there was some territorially aggressive behavior towards new guests arriving in the home as well.

After sitting down with the guardians to discuss the situation, I learned a number of things that most certainly could be contributing factors; both males are intact, the house is cozy and the guardians only had minimal rules in place.

For some dogs, you can get by with minimal structure. But when you have multiple dogs in a confined home with testosterone flowing, a lack of structure can result in dogs starting to compete or challenge one another.

Its possible these dog fights have been the result of proximity to a water bowl or the door to the back yard that the dogs went through excitedly. Well, let me rephrase that. Star usually shoved his way out of the door.

I suggested that the guardians start adding structure to letting the dogs out the door. By making the dog relax and settle down and sit before letting them out, the dogs will be more balanced which can help eliminate some factors contributing to Star’s aggression.

When I made this suggestion to the family’s mother, she scoffed and said “good luck with that. No way you can stop him when he wants to go.” Lets just say I took that as a challenge and walked her through doing just that in the video below.

Adding some structure and limiting Star’s access to the back yard to a predefined behavior first is just one example of a way to assume the leadership role in the home. It will take a little practice, but based on how quickly Star adapted, I think this is going to be more challenging for the humans to change their behavior than it will for the dogs.

The dog on dog aggression Star was displaying is most certainly a result of the lack of structure from the humans. These dogs have lived together as friends for years and its probable that this problem has been simmering for a while.

In order to stop the dogs from fighting and bring them back to balance, the humans are going to need to add structure to the day to day routine. As a dog behaviorist I have had a few clients think the problem lies else where. This is understandable, its hard for some humans to understand when the dogs used to get along so well for a long time.

But the good news is, dogs live in the now and adapt quickly. If the humans can assume the leadership role by demonstrating leadership qualities (not through dominance, but through their actions), Star’s aggressive dog behavior can be curbed and eliminated.


  • Introduce rules (must sit at the door to go out, sit for permission to eat, sit to ask for attention, no jumping up, etc) and boundaries (respect a 1 foot bubble of personal space, no jumping up, stay a few feet away from any human eating food) and consistently enforce them.
  • Stop petting the dogs (especially Star) when they paw or nudge for attention.
  • Practice the Focus exercise with each dog 2 or more times a day.
  • Start claiming a one foot bubble teach the dogs to respect personal space of humans. Allow them to get closer with invitations, not by shoving their way into your lap.
  • Stop shoving or using any physical corrections with the dogs.
  • Immediately stand up when any of the dog’s climb up on them.
  • Never punish a dog for growling. Especially when near another dog that its growling at.
  • Never spank one of the dogs when its acting aggressively. Instead redirect it or remove it from the trigger.
  • Start rotating the order the dogs are taken out to train in the back yard. Ideally selecting the calmest dog.
  • Rotate the order of separation as well. Don’t consistently leave Shiloh with one dog over the other. Isolating Star to herself will likely increase his aggression.
  • Increase the dog’s exercise. Consider working them out multiple times a day to help eliminate any excess energy or hormonal frustration.
  • Get the male dogs neutered.
  • Use the escalating consequences to disagree with unwanted actions or behaviors.
  • Stop petting the dogs when excited and NEVER when Star is acting aggressively.
  • Start filming the dogs together and review it after to identify their warning signs to watch for in the house. When any signs are displayed, immediate increase the distance between the dogs. Do this in a calm manner.
  • If there is another dog fight, immediately after separating the dogs, sit down and write as much detail as possible in  a journal about the encounter (time of day, location, energy, sounds in the room,  who was present, objects present, etc). By journaling immediately after each dog fight, the guardians may be able to identify trends or factors that contribute to, or trigger a dog fight.
  • Start walking Star and Tazy together every day, preferably after being worked out in the back yard and given a 10-15 minute recovery time (working Star last). This daily walk needs to be a daily activity until the problem is abated for good.
  • Do not let either dog walk in front of the other on the walk. Keep one on each side of the handler.
  • Do not allow the dogs to mark on this duo walk.
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This post was written by: David Codr

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