Dogs are not born with guarding behaviors, but may learn at a very young age that guarding earns them valuable resources. Think about a litter of 10 pups, with only 8 places to nurse, a pup may learn that they must be pushy or even assertive to eat. I am not saying that all pups in large litters are more likely to be guarders, a good breeder will notice if one pup becomes too pushy and separate the group so this behavior is not practiced.
What I am saying, is that guarding a resource is a behavior that is learned through practice and having small successes over a period of time. The dogs that learn to guard in my opinion are the smart dogs, while not acceptable in the family dog, you can’t argue that they are thinking dogs.
Can a dog go from guarding items, food or even thresholds in one home to not guarding in another? Many dogs learn that what worked in one environment, may not work or be necessary in another. For example, if a worried dog stands and barks at you in a doorway and you turn and leave, this dog will certainly try this behavior again as it worked for him. However, if you ignore his barks and walk right past him, he learns that standing his ground does not work and may try another behavior. Depending on his confidence level, he may try to bite next time or he may offer an appeasing behavior like a body wag as if to say, “Okay, let’s be friends.”
If a small dog stands on mom’s lap and growls at the approaching dog, when the approaching dog turns and walks away, the dog growling learns that this behavior works and will certainly use it again. If however, this small dog begins to get stiff or stare at the approaching dog, the owner may choose to quickly plop the small dog behind the couch as a consequence, no emotion or words needed. With the small dog on her lap again, she will offer her a treat and use verbal praise when she allows a pack member to approach. Counter Conditioning new rules in the same environment, this small dog learns that when she guards, she loses the valuable resource and when she complies, she gets to keep her resource and gets a bonus treat too! With consistent repetition and knowing what you are rewarding most dogs can learn not to guard items in old and new environments.