Beak

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 can 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.

Read more about Beak:  Etymology, Anatomy, Egg Tooth, Color, Dimorphism, Functions, Billing, Beak Trimming

Famous quotes containing the word beak:

    Then the bird
    breaks with his beak the thread
    of dream within him,
    and the tree unrolls
    the shadow that will guard it
    throughout the day.
    Denise Levertov (b. 1923)

    His beak is focussed; he is preoccupied,

    looking for something, something, something.
    Poor bird, he is obsessed!
    Elizabeth Bishop (1911–1979)