The Dodo (Raphus cucullatus) is an extinct flightless bird that was endemic to the island of Mauritius, east of Madagascar in the Indian Ocean. Its closest genetic relative was the also extinct Rodrigues Solitaire, the two forming the subfamily Raphinae of the family of pigeons and doves. The closest living relative of the Dodo is the Nicobar Pigeon. A white Dodo was once incorrectly thought to have existed on the nearby island of Réunion.
The Dodo's external appearance is evidenced only by paintings and written accounts from the 17th century. Because these vary considerably, and because only a few sketches are known to have been drawn from live specimens, its exact appearance in life remains a mystery. Similarly, little is known with certainty about its habitat and behaviour. Subfossil remains show the Dodo was about one 1 metre (3.3 feet) tall and may have weighed 10–18 kg (22–40 lb) in the wild. It has been depicted with brownish-grey plumage, yellow feet, a tuft of tail feathers, a grey, naked head, and a black, yellow, and green beak. It used gizzard stones to help digest its food, which is thought to have included fruits, and its main habitat is believed to have been the woods in the drier coastal areas of Mauritius. One account states its clutch consisted of a single egg. It is presumed that the Dodo became flightless because of the ready availability of abundant food sources and a relative absence of predators on Mauritius.
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young. The terms beak and rostrum are also used to refer to a similar mouthpart in some Ornithischian dinosaurs, monotremes, cephalopods (see Cephalopod beak), cetaceans, billfishes, pufferfishes, turtles, Anuran tadpoles and sirens.
Although beaks vary significantly in size, shape and color, they share a similar underlying structure. Two bony projections—the upper and lower mandibles—are covered with a thin keratinized layer of epidermis known as the rhamphotheca. In most species, two holes known as nares lead to the respiratory system.