A Yorkshire Terrier in Toulouse, France survived for nearly a month by eating the dead body of its 64-year old deceased owner.
Such occurrences are not that rare, as Brian Palmer notes over at Slate magazine:
Dogs are perfectly willing to eat human corpses, and there's no evidence that they treat their masters differently than any other dead body. Many cultures consider dogs unclean precisely because of their tendency to scavenge our remains. In The Iliad, Homer makes nine references to dogs eating dead bodies. Dogs consumed the body of Jezebel, a princess in the Old Testament, after her defenestration. There is evidence that ancient Romans considered the low-hanging cross a crueler form of crucifixion than the high version, because it enabled dogs to rip the body apart. There are even a few secular historians who believe that Jesus' body was eaten by dogs, and that his acolytes fabricated the story of a reverential entombment as a sort of coping mechanism. Some Muslim communities in East Africa revile dogs because they believe that canines ate the body of the Prophet Muhammad. Modern dogs exhibit the same behavior, and many have eaten their fallen masters.