Don’t be the tug toy in the war between your dogs.
What you may perceive as two dogs showing the jealous behavior of a human is likely a power struggle between the dogs. Dogs have an innate pack mentality. Part of the pack mentality is that the alpha dog gets first dibs on food, toys and even humans.
Learn about your breed. Some dog breeds are more apt to play nice with others. Other breeds will fight to the death, so it is important to understand what will likely happen if your dogs fight. Certain breeds, such as malamutes, have problems living in homes with same sex dogs and may require careful training before a fight breaks out.
Teach your dogs to respect humans. Do not allow them to growl at you, nibble on your fingers or to chew on your possessions. When a dog growls or nibbles, tell him “no” in a definitive voice and redirect the dog’s attention onto something else. For example, if you catch your dog chewing on your slippers, take the shoes and give him something of his own to chew on, like a rawhide chewy.
Respect the pack. You dogs will decide for themselves who will be the alpha dog. If you have male and female dogs, you may have a male and a female alpha. Observe the dogs as they interact. If one dog usually walks through the door first or eats first, he is likely the alpha. If you are petting a dog and the alpha walks up, let the dog you are petting walk away and show proper respect to the alpha. Do not reprimand the alpha for being dominant or reward the other dog for standing up to the alpha.
Use methods other than your hands to break up an unavoidable fight. In the excitement, you may be bitten. Make a loud noise or throw water on the dogs to break it up. Use a broom or a rake to get between them. Avoid coddling one dog while reprimanding the other, as it will only cause more fights later.
Schedule obedience training if one dog seems to start the altercations repeatedly. The training is for both you and your dog. Your dog needs to show you proper respect and you need to learn how to constructively and humanely make sure your dog knows who is in charge.