Answer: Bones

There’s one thing you can always be certain of in nature: if there is something that can be eaten, then there is some creature, big or small, out there eating it. Be it hard to reach pine cone seeds, lichen sprawled across Siberian rocks, or even the bones left behind by other animals, there is a creature that feasts on just about everything.

That last and rather improbable item, bones, is exactly how the bearded vulture survives. Long after the other predators and scavengers have abandoned the body of their prey, long after the carcass is picked clean of meat (they usually disdain the actual meat), the bearded vulture swoops down and proceeds to devour the bones, sustaining itself off a diet that is 85-90 percent bone marrow.

Like other vultures, it has a proverbial cast iron stomach with extremely acidic digestive juices which make short order of outright dissolving the bones and releasing the nutrients therein. If that sounds particularly curious to you, it should: the bearded vulture is the only bird in the world adapted to (specialized in) feeding on bone marrow and stands alone in its particular dietary niche.