What Does Keratin Do for Birds?

Four different types of macromolecule -- lipids, carbohydrates, nucleic acids and proteins -- make up the living cells in most organisms. All four types are important in their own way, but proteins are the primary structural molecules for animal cells. Keratin is one of the most important proteins among vertebrates. Birds have it in their feathers, beaks and feet.

  1. The Protective Protein

    • Keratin is one of the most common biological materials; mammals, reptiles and birds all use it in various parts of their body. Keratin is a primary component of hair, horns, fingernails, feathers and the outermost portion of animal skin. Animals produce keratin, a structural protein, in layered sheets held together chemically. Keratins are stable, light and durable proteins that are insoluble in water.

    The Foundation of Feathers

    • Keratin is the primary structural component of bird feathers, though their exact chemical compositions vary from one type of feather to another and from one species of bird to another. Some bird feathers contain melanin -- the pigment that produces dark brown or black colors. Feathers with melanin are more abrasion-resistant, and they last much longer than feathers without melanin. According to Richard Bonser of the University of Reading, the structure of the keratin in feathers, rather than its chemical composition, gives feathers their strength.

    Keratin's Keen Edge

    • Bird beaks have evolved to reflect the way each species obtains and manipulates foods. They also use their beaks to grasp items, build their nests and defend themselves from predators. Accordingly, beaks must be very durable. Skin grows over the beak bones of birds, and the outer layer of this skin produces keratin. The keratin dries and hardens as it ages, becoming durable in the process. As keratin layers wear, new layers replace them. The process of replacement helps keep the sharp edges on beaks of birds such as hawks and owls.

    Keratin-Covered Kicks

    • In addition to composing feathers and beaks, keratin is a chief component of the scales covering bird feet. Here, keratin̵7;s durability helps to protect the feet, which are often in direct contact with cold and wet surfaces. The toenails or talons at the ends of the birds̵7; digits are also composed primarily of keratin.

    Keratin Dust and Disease

    • Down feathers are the short, soft feathers that typically serve to insulate birds. In some species, these feathers break down over time and create harmless keratin dust that helps to waterproof the birds' feathers. However, in many pet species such as African grey parrots and cockatoos, the presence of keratin dust can indicate the presence of psittacine beak and feather disease.