The bearded vulture is the only known animal whose diet consists almost exclusively (70 to 90 percent) of bone. This species remains one of the most endangered species in Europe. It nests on cliffs high up in te mountains. This bird is (37–49 in) long with a wingspan of (7.6–9.3 ft).[9] It weighs 4.5–7.8 kg. The bearded vulture has learned to crack bones too large to be swallowed by carrying them in flight to a height of (160–490 ft) above the ground and then dropping them onto rocks below.