Dogs and Possession Aggression

Dog Aggression and Resource Guarding

Jack Russell Terrier in backyard on a sunny day in the shade growling and protecting a bin of tennis balls
All these tennis balls belong to me!. Jim Corwin / Getty Images

Does your dog growl or snap at others when he is around food or favored objects? It might be possession aggression. Dog aggression can be a serious problem for dog owners. In order to prevent or change aggressive behavior in dogs, it's important to know exactly what is causing the aggression. The following information can help you determine if you're dealing with possession aggression in your dog.

What is Possession Aggression?

Possession aggression in dogs is also sometimes referred to as food aggression or resource guarding. In cases of possession aggression, dogs growl, snap, or bite in order to protect a resource from being taken away by another dog or person. It's your dog's way of saying, "Back off, this is mine!" Resources may include food, toys, or other valued objects.

Keep in mind that what your dog considers an object worthy of possessing may not be something you think has any value. For instance, some dogs are just as likely to snarl and snap over a tissue they fished out of the trash can as a big meaty bone.

Causes of Possession Aggression

Often, possession aggression in dogs is genetic. Some dogs are just born with a genetic inclination to protect their food, toys, or other objects. Even puppies as young as a few weeks old have been observed growling over a food bowl.

Some dogs may learn to be aggressive in situations where they feel there is competition over resources. For instance, a single dog in a household may never show signs of possession aggression, but if you add another dog, there may be squabbles over toys or food bowls. It's not uncommon for dogs who spend a long time in an animal shelter to develop a problem with possession aggression. This is because they perceive the other dogs as competition for a limited number of resources.

Signs of Possession Aggression in Dogs

  • The dog growls when a person or another animal approaches his food bowl.
  • The dog growls, snaps, or bites when someone tries to take away a toy or bone.
  • The dog fights with other dogs over bones, toys, or food.
  • The dog's body stiffens or shows other signs he may bite when people or other animals approach while he's eating or playing with a toy or bone.

Degree of Dog Aggression

Different dogs can display different degrees of aggression. Some dogs may only show aggression over one specific object and nothing else. For instance, some dogs may not care if people or other animals approach him while he's eating or playing with a toy, but snap or growl if someone approaches him while he's chewing on a pig's ear. Other dogs, however, may display aggression over anything he finds around the house. This can include food, bones, toys, children's toys, tissues, and other random objects. It may even your belongings, like shoes or items of clothing.

There is also a difference in the way in which dogs display aggression. Some dogs never do more than curl a lip or let out a small growl. Other dogs may give serious bites to someone who approaches while they eat.

It's also possible for aggression to escalate over time. A dog may start off with a small growl over his food bowl, but if his warnings are ignored, he may resort to biting to protect the things he thinks of as his. 

How to Deal With Possession Aggression in Dogs

If the sign your dog exhibits is growling, be sure you are dealing with the growling properly. The worst thing you can do is to force your dog to give up the item he is protecting. You could get injured and your dog will learn nothing. Instead, teach your dog to trust you around his treasures. It's better to find a way to convince your dog that giving up the item means something good will happen.

Try introducing something your dog may find more valuable, like a special treat or a new toy. If your dog is holding the item he is guarding, you can use the "drop it" cue to get your dog to give up the item. Just make sure you have a valuable reward! After your dog stops guarding and gets the other reward, you can let him have the item he was guarding back. Repeat the exercise often, each time your dog is resource guarding. Over time, he will hopefully learn that there is no need to protect his stuff.

Some trainers recommend a multi-step process that conditions a dog to willingly move on from a resource. This can work especially well with food. Place several bowls around a large room. Put food in one bowl. While your dog eats, add a better food to another bowl that is at a distance. Do not get close enough to evoke an aggressive response, just let your dog see that you are offering a valuable alternative. Continue to add more valuable food to additional bowls, but stop if your dog shows aggression.

If your dog is actually trying to bite, you must be very careful. If you are not seeing improvement on your own, or if your dog's aggression is getting worse, consider getting help from a dog trainer or behaviorist to correct your dog's behavior.