The bearded vulture
is the only known animal whose diet consists almost entirely (70-90%) of bone. It is capable of swallowing a sheep’s vertebrae whole. The bird’s stomach acid has been estimated to have a pH of 1, so even large bones are digested within 24 hours.
Christ that’s so metal
I also want to point out that these birds aren’t red! They are actually black and white!
The red color comes from rubbing themselves in red mud/dirt/dust, to paint themselves for display. Territories with the reddest soil are highly contested and defended, so that you can tell who is big and strong by how red they are:
Dragon birds who eat bones and wear makeup.