Dogs can guard all kind of things - people, food, spaces, objects. The good news is that this behaviour can often be modified successfully.
What is Resource Guarding
Resource guarding (also known as 'possession aggression') is behavior a dog may display in order to control access to a valued item or space. A valued resource includes anything of value to that particular dog. Just as people value different items, so do dogs. A dog may feel the need to guard food, a bone, toys, space, another dog, or even a human. When a dog is actively guarding a resource, he might display defensive behavior to keep another dog, person, or animal away from the item or space.
Resource guarding is a normal, natural survival behavior that all animals, (including people) experience in varying degrees. The severity of the guarding behavior can range between mild and serious.
What Resource Guarding May Look Like
Many of us know it when we see it; the dog with a bone that stands over it with his head held low, body tense at your approach. Some dogs remain quiet and stare intensely at the threat of approach, others growl, bare teeth, lunge or air snap (also known as 'air bite'). These behaviors are used remove a perceived threat to the resource being guarded. Some dogs (after their warning signals have been ignored) resort to a bite in order to remove the threat.
Here is a list of sample behaviors or warning signals a dog guarding a resource might display:
When a threat approaches they may stop, freeze or display slow body movements.
Intense staring and/or wide eyes.
Lip licking, flicking the tongue out or nervous or agitated movements with the mouth.
Hovering over or near the item, sometimes with the head low and eyes focused on the threat.
Low or deep growling, baring of teeth, lunging forward, or air snapping.
Biting comes in many forms. As soon as teeth make contact this is considered a bite, whether the dog causes injury or not. That the dog decided to lunge and bite, but shows restraint from causing injury does not mean the dog did not bite. Some dogs will bite and nick the skin, causing a bruise, or will puncture skin. Some dogs bite and quickly release (I call this a 'snake bite'). More serious and dangerous bites can occur when the dog continuously bites and/or holds on without releasing.
Muzzling punching. The dog will either gently or forcefully bump his nose/muzzle into the threat. This is known as a closed mouth bite and in some cases can be a very serious warning sign.
Fixated or intensely focused on a threat. Typically, the dog’s eyes might be glued to the threat and will be aware of their every movement. Some dogs might follow the threat around in an intense way when guarding. I find this occurs when a dog may feel very concerned or conflicted.
Body Blocking or Body Positioning. This typically silent behavior is intentionally used by dogs to block access to their valued resource. For example, you might find they will stand over or in between their resource and other people or dogs. If a dog is guarding a human, say their owner, you may find that they lean against that person, usually while staring at the threat. Or they may position themselves by standing in between the threat and the resource.
Some dogs will vigilantly look at the threat, then look back at the resource, then again at the threat and again at the resource. This is also a silent behavior that is often missed.
Why Dogs Resource Guard
Some of these reasons include:
Feeling threatened due to insecurity and an inability to cope.
Changes in the environment (a new baby, a visitor, a new dog, someone entering or exit a threshold or doorway, etc.).
Competition for resources.
Feeling like the resource might arbitrarily be taken from them, which could cause a dog to feel conflicted, vigilant, concerned, or angry.
Feeling the need to control the outcome of the environment.
Addressing Resource Guarding