Dogs are social animals with a strong urge to form structured packs. They normally live in harmony, typically only encountering conflict when the hierarchy is unclear. Same sex dogs are more prone to fighting than mixed couples, especially males between 10 and 12 months old, as they have a testosterone peak at this age. Removing the causes of conflict is a good start toward fixing the problem. If it continues, supervision and controlled socialization will help you to teach your pets how to get along.
Have a friend or family member take one dog on leash and you take the other. Allow the dogs to interact.
Praise both dogs verbally while they’re passive and well behaved.
Look out for signs of aggression, such as growling, flashes of teeth or posturing. Stop the praise, then wait. Dogs don’t always fight when they feel aggressive. Stopping the praise will teach the dogs that when they’re aggressive, positive things are removed.
Guide both dogs calmly away with the leashes if they begin fighting. Give them a time-out. Only allow the dogs to socialize when supervised in the beginning when you’re trying to stop the fighting. If you catch them fighting once you’ve started to allow unleashed socialization, distract them with noise to stop the fight.
Set clear and equal boundaries for the dogs. If Lucky isn’t allowed on the sofa, then neither is Fido. By treating one dog differently than the other, you invite tension and conflict as one dog feels usurped.
Be consistent. If you don’t tolerate aggressive play on a Monday, but you let is slide on a Tuesday, the dogs won’t understand what is and isn’t acceptable.
Favor the dominant dog. It’s hard to do, because you’re a complex human, but male dogs are simple, uncomplicated beings. They crave food, security from the pack and the chance to reproduce with females. Greet the dominant dog first, feed him first and allow him to deal with challenges to his superiority by himself. Dogs rely on hierarchical structure, so they need a line of command. The inferior dog won’t feel sad that he’s not top dog, but should he attempt to challenge for supremacy, let nature take its course.
Feed the dogs separately. Although access to females is the most likely cause of friction between two male dogs, food is also a common source of aggression. Both dogs are programmed to protect their food jealously. If you put both bowls down side by side, the dog who finishes first may be tempted to sniff or even try to steal the other dog’s food. This will lead to a fight in many cases. Keep the dogs separate until both have eaten.
Provide lots of toys. If there are limited toys, this increases the chances of fighting over resources. Male dogs will guard their resources if another male shows an interest.