culmen beak anatomy - Search
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  1. Overview

    The beak, bill, or rostrum is an external anatomical structure found mostly in birds, but also in turtles, non-avian dinosaurs and … See more

    Etymology

    Although the word "beak" was, in the past, generally restricted to the sharpened bills of birds of prey, in modern ornithology, the terms beak and bill are generally considered to be synonymous. The word, which date… See more

    Anatomy

    Although beaks vary significantly in size and shape from species to species, their underlying structures have a similar pattern. All beaks are composed of two jaws, generally known as the maxilla (upper) and mandible (l… See more

    Egg tooth

    Full-term chicks of most bird species have a small sharp, calcified projection on their beak, which they use to chip their way out of their egg. Commonly known as an egg tooth, this white spike is generally near the tip of the up… See more

    Color

    The color of a bird's beak results from concentrations of pigments—primarily melanins and carotenoids—in the epidermal layers, including the rhamphotheca. Eumelanin, which is found in the bare parts of many bir… See more

    Dimorphism

    The size and shape of the beak can vary across species as well as between them; in some species, the size and proportions of the beak vary between males and females. That allows the sexes to utilize different ecological … See more

    Development

    The beak of modern birds has a fused premaxillary bone, which is modulated by the expression of Fgf8 gene in the frontonasal ectodermal zone during embryonic development.
    The shape … See more

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