Why do dogs bury bones in the ground? Because they can't bury them in trees! You may have heard that old chestnut, but in reality, burying bones is a serious business for dogs that is driven by heredity and instinct.

To understand why your dog buries his bones, even though you feed him twice a day, you have to understand his nature. You can do this by looking at your dog's genetic heritage. Although dogs have been around for millions of years, they have only been domesticated for a few thousand years, and they spent a lot of time developing behaviors that helped them to survive.

One of the most important behaviors had to do with finding and maintaining an adequate food supply. Being carnivores, dogs might sometimes kill a prey animal large enough to feed the entire pack, like a moose or a mammoth. Alternatively, when small prey animals were abundant , they might kill many of these bite-sized creatures. Either way, they often found themselves with more food than they could eat at once. However, they could never be sure when they would be able to find and kill another prey, and much time could pass – sometimes weeks – without them finding another meal. So to be on the safe side, they carried the bones, which were filled with nutrient-rich marrow, back to their lair, and buried them nearby. When food was scarce, they could always rely on the bones to keep them fed.

This process is called caching or hoarding, and it is common among dogs, wolves and foxes. In fact, other animals practice a form of caching; squirrels gather enough nuts to last through the winter, and camels store enough food and water to last for several days in the desert. Our domesticated dogs may have their food handed to them each day in sufficient quantities, but they still carry this caching trait and bury their bones or toys in the back yard – or even under your pillows – to guard against a possible shortage of food.

So, why do dogs bury bones in the ground? Because it's in their nature.