Some protection of a dog's possessions is normal. A dog shouldn't have to give up his bone to another dog. He's allowed to tell the other dog to go get his own bone, thank-you-very-much!

However, being overly protective of his possessions is not healthy for him or safe for others. It's one thing if a dog walks right up to him and tries to snatch a bone from his mouth, and he gives a snarl, growl, or bark to let him know that's not ok. It's quite another thing if he erupts into aggression when a dog just walks near him when he has a bone. Also, YOU should be able to take something from him anytime. If he picks up something that could hurt him, a chicken bone for instance, you need to be able to take it from him without a struggle. Many dogs will accept that you can take anything at anytime, and it's ok, but some dogs need to be convinced.

Keeping the Peace among dogs

It's rude for a dog to try and steal something from another dog. Even stronger dogs recognize the right of a weaker or smaller dog to maintain what is his. However, some dogs are just bullies! The stakes rise the more value the dogs place on an item. If you have multiple dogs, fights can erupt over high value items. To keep the peace in your household, know the value your dogs put on certain items. Never let them have high value items unsupervised. Interrupt any attempts by one dog to steal from another dog. It's helpful to have one more toy on the floor than you have dogs. That way, if a dog gets bored with the toy he has, there is another option besides stealing his buddy's.

What's Mine is Mine and What's Yours is Mine

Possession equals ownership in dog-dog interactions. However, it's different with dog-human interactions. Everything is yours. You just share it with your dog. All dogs aren't born knowing this distinction. They have to be taught. Some are easier to convince than others. If they don't recognize you as their leader, they aren't going to give things up without a fight. Remember, it's rude for a dog to try and steal something from another dog. If he doesn't understand that everything is yours and you only share it with him, he will think little more of you than a rude dog trying to steal his bone! If you try to take something from your dog and he growls at you, work on your leadership exercises.

If your dog is growling at you when you try to take something from him, try working out a trade. If he gives up whatever he is guarding, he gets a yummy treat. Keep practicing with this until he realizes that he's not going to go without, even if he gives up his prize. You will need this if he ever picks up something that could hurt him. As he learns to give you his possessions when asked, phase out the treats and only treat randomly.

When to call for Help!

Guarding something in one's possession is normal for dogs (just not safe when done with humans). It's NOT normal for a dog to be paranoid about his possessions. If your dog becomes aggressive if someone (dog, human, or other) just LOOKS at him while he has a prize, or if someone walks near him and doesn't even notice his prize and he becomes protective, this is a serious problem. You need the help of a professional. Dogs who over-guard possessions have psychological issues that the average pet owner is not equipped to deal with. Get help, not only for the safety of those who come into contact with your dog, but for your dog's own mental health. A dog who is paranoid about having his possessions stolen is not a happy dog, nor is he a "safe" dog.

Additional Resources

Mine! by Jean Donaldson - a book all about resource guarding in dogs. The book is written more for dog training professionals but has helpful advice for any dog owner.

Resource Guarding - prevention and treatment plans.