I don't know who did the nibbling, but it was done just before we hit the clearing.
There was still plenty of plump juicy flesh on these bony parts. Yum-yum.
UPDATE: I didn't know it at the time, but a little research revealed that the bony head parts above once belonged to a rabbit. I would not have guessed that rabbits had such a long lower tooth but they do. The overall dentition is very indicative of a herbivore and the larger front teeth plus the placement of the small back teeth spells out the rest.