ocr: BEAKS Hollow Beak I HE which VISIBLE grows PART over of the a beak bird's is upper made of and keratin, lower jawbones. The toucan has an unusually large beak. HARD SURFACE In some species, the beak is more than 7 inches The outer sheath is hard (18 cm)long. When a toucan sleeps, it swivels and strong, but quite light its head backward and rests its beak on its back for support. LIGHTWEIGHT BEAK BONE The inside of the bill is mainly Thin jawbones lie hollow, with a network of underneath the sheath supporting struts DIDYOU KNOW?
