Household Dog-on-Dog Aggression
Written by Susan Engel, Certified Trainer

Dogs are social animals by nature and for the most part will live without any real confrontation towards their doggy housemates. Owning more than one dog can be a wonderful, rewarding experience and many families live with multiple dogs peacefully without any incident.
However, when the pack (which all members of your family are included) becomes unstable and the ranking status becomes unclear; fighting may occur. These confrontations may range from simple squabbles to serious dog fighting which may result in injury and trips to the veterinarian. Dogs fighting in the home is upsetting, dangerous and no way for you or your dogs to live.
The Workings of Household Dog Aggression
What is a dog fight?
Serious dog fights are unable to be broken up by voice commands. The dog fights may result in puncture wounds to one or both of the dogs; however, injury does not always occur. Fighting may become more frequent and more serious as time goes on.
Who Fights?
Dogs of the same sex have a higher chance of fighting. Two males will fight more often; however, a fight between two females may be more intense. Dogs that are not spayed or not neutered have a higher chance of fighting. Some breeds have a higher chance of fighting because of the inherent characteristics of the breed. Dogs closer in age have a higher chance of fighting; however, a young dog and an older dog may also fight. It is not unusual for dogs that have been harmonious in the past to begin fighting when one or both become socially mature (between ages 9 months & 2.5 years of age).
Why do dogs fight?
Resources. Most fights begin over resources: toys, food, doorways/space and attention from the owners. Unclear Pack Ranking. It is important for you to realize that a dog pack (of which the owners are a part) is not a democracy. Dogs live through a ranking system similar to the military. Each dog should know it’s own place however if the ranking system is not clear, especially if it is not clear that the human members of your family are the top ranking member, fights may occur. (This does not mean you should be harsh, hit or yell at the dogs…these are not characteristics of a strong leader). In most cases, owners unknowingly contribute to the pack instability. Owners may have a clear understanding as to why some fights begin however, are baffled as to why other start…dogs always understand the reasons for fighting. The subtleties of posture, glances and inter-pack challenges may be missed by many owners.
Breaking-up Dog Fights
It is a myth that ‘letting them fight it out’ will resolve the issues the dogs have with each other. This is also very dangerous and may lead to your dogs being seriously injured or killed. Many owners are injured when trying to break up a dog fight because the dogs may re-direct the biting to any body part they see, be it human or canine.
Preventing Dog Fights
If there has been a serious dog fight, it will be important to completely separate the dogs until you are able to get assistance from a professional trainer that has had success assisting with this behavior.
Be sure that you remove the resources that are sparking the fights, like toys or treats. Feedings should be done separately and the dogs should be taught not to run thru doorways, especially those to the outside but sit and wait to be invited thru.
Controlling Dog Fights
Dogs that have a strong, firm leader in the pack do not fight. It will be your job to become this strong leader in their minds. Because dog behavior and pack communication is complex; you most likely will need a professional trainer who is skilled in this area to assist you.