It depends so much on so many things.. location.. if in a place there is little food... whether it is a wild dog.. whether it was related to the pup... there is more to this then meets the eye.. even dogs normal habits in general would come into play.... some dogs bury everything.. some dogs do this in attempt to survive..some dogs do this so predators won't smell the body.. she might think this is a way to keep them away from her and her puppys..{if she has any} so many things..