Resource guarding is a natural, normal canine behavior.  For wild animals, allowing other dogs or animals who come along when they are eating – to take their food from them, would mean death for their species.  So how did this natural, normal behavior become so evil that many dogs have died as a result?
Before the 1990’s, canine behavior assessments were conducted at shelters in a reckless manor.  Millions of homeless dogs and cats were euthanized yearly and any show of aggression, including resource-guarding, was a sure way to end up on the euthanasia list.
Through spay and neutering and education programs, shelter numbers declined and animal protection professionals made thoughtful decisions through more standardized assessment processes.  Still, the scary behavior dogs’ display when protecting what is valuable made them highly likely to be euthanized as it had the stigma of being an identifiable trigger for aggression.
In the 1990’s, a resource-guarding assessment tool called the “Assess-A-Hand”, which was a fake rubber hand on the end of a stick, was placed near the subjected dog who was in possession of a valued item to study his response if approached by a human.  Animal protection professionals were convinced that, in order to keep the public safe, it was logical to refrain from adopting dogs who showed identifiable aggressive behaviors, including guarding.  Euthanizing all dogs who displayed any sign of resource-guarding, though well-meaning, was an overreaction.
Today, the continuum of guarding behavior has a range of outcomes for dogs displaying any amount of guarding, with extreme cases being euthanized.  Thoughtful placement on the continuum along with appropriate options for the dogs of each designation, managed and modified resource-guarding behaviors which, in turn, determined positive outcomes for more dog.  However, each shelter and rescue organization makes its own decisions on the level of guarding they will tolerate when considering suitability for placement.
Should a pet owner choose to manage their dogs guarding behavior, they must have no small children in their home.  They may want to feed the dog in a separate room with the door closed.  If there is more than one dog, this is a must.  When giving multiple dogs’ high-value treats, it is a good idea to separate them by using crates, baby gates, and closed doors.  A guarding dog can be trained to trade for a treat when taking something from them.  It is crucial to evaluate the home environment to determine if management is a realistic long-term answer for them.  There are some situations which suggest that modification may be needed in addition to management such as children living in or regularly visiting the home; one or more adults in the home cannot be depended upon to adhere to the management program; random fierce and unpredictable guarding behavior from the dog.  If the dog needs behavior modification, then a stringent management program must be in place.
Dogs guard because they fear they are losing something of value and it is a fear that is learned through experience.  Others have guarded from a very early age; as puppies showing resource-guarding behaviors to littermates and humans.  However, the goal is to convince the guarding dog that, when in the possession of a resource, a human approaching them is not a threat to their resource but could be even more good stuff.