Why do dogs like to bury bones?

Dogs are not scavengers, just smart hunters:Its actually a fact of heredity. Whether or not your dog will bury bones depends on his/her family line. Back in the days before they became domesticated animals they would hunt in packs, and bring back enough food for the whole pack to feed. The problem was that food was enough for them for that day, but not enough for the next day. They faced a problem, sometimes they may not even find prey the next day, or week for that matter. That caused them to adapt and develop the habit of burying the nutrient rich bones just in case of emergency. That would be enough to sustain them until they were able to catch prey again.

Also, You may think that they forget about their bones or even treats, but, if the dog remains well fed, or doesn't get hungry easily, he/she will not need to recover the bone. The same goes with treats, except the treat will decompose and the dog will not recover it because it is no longer fit for nutrition. Dogs have very keen senses and can tell when food is spoiled. But sometimes if they are hungry enough, they will eat it.

For a more elaborated story see the link below.