Dogs bury objects due to an evolutionary instinct to store and protect bones and food from scavengers. Known as cache behavior, it is common for domestic dogs to bury bones, toys and other objects, according to the Wolf Education & Research Center.
For the ancestors of modern dogs, burying objects was a crucial part of survival. Cache behavior offered early dogs an effective way to store and protect their food. The ASPCA states that while modern dogs mostly dig to create a warmer or cooler place to rest, they frequently bury bones, toys and other objects due to an instinctual urge that allowed their ancestors to protect uneaten food.