Cassowaries use claws on their inner toe (digit II) for defence and have been known to disembowel people. All birds, however, have claws, which are used as general holdfasts and protection for the tip of the digits. The hoatzin and turaco are unique among extant birds in having functional claws on the thumb and index finger (digits I and II) on the forelimbs as chicks, allowing them to climb trees until the adult plumage with flight feathers develop. However, several birds have a claw- or nail-like structure hidden under the feathers at the end of the hand digits, notably ostriches, emus, ducks, geese and kiwis. Amphibians The only amphibians to bear claws are the African clawed frogs. Claws evolved separately in the amphibian and amniote (reptiliomorph) line. Arthropods The scientifically correct term for the "claw" of an arthropod, such as a lobster or crab, is a chela (plural chelae). Legs bearing a chela are called chelipeds. Chelae are also called pincers. See also Horse hoof Dactyly References External links Rat's Claws, also explains much about mammalian claws in general. Animal anatomy