In the wild, it’s kind of like their fridge. If they have a surplus of food or food that takes a longer time to eat, like bones, then they want to hide it so that another dog can’t run up and grab it. Burying it keeps it safe. If you look at the dog in the domestic setting, they don’t want for anything. They have a food bowl filled up every day and toys all over the place, so they probably think, “Well this is extra. I don’t need it now, but I’d like to save it for the future.”