Have you ever seen your dog bury a bone? This is a common behavior that is shown in many TV shows and animal inspired cartoons.
You dog buries his or her bones due to a natural instinct. This is from their "wild side," in which wild dogs need to hide their bones and valuables during certain times. By doing this, they create a "Stash" that they can later find at a later time. This allows those wild dogs to hide valuable things and food stores for when times are more calm. They hide them form other predators and also acces these food stores in times when food sources may be scarce.
So this is basically a survival mechanism, but is also a wise strategy by dogs. By digging deep enough into the ground, the dogs could place food into cooler spots within the soil. They would place the food in there and then cover it up. The dirt covering served two purposes: hiding the food and creating an insulation barrier. The cooler earth would serve as a sort of refigeration for their precious food sources.
Now that you know why your dog exhibits this behavior, check back later to see how you can try to prevent your dog from digging.
Article written for Seville Wadsworth Veterinary Clinic, by Jeff Fink D.V.M.