Beak

The beak (Latin rostrum ) is in zoology, the forward pointed expiring mouth tool in birds, platypus, beaked whales and cephalopods. It serves as a replacement for developmentally no longer existing teeth.

In birds, the beak is used only rarely for chewing, exception would be, for example, the parrots, but mainly as a gripping tool for receiving, tearing or cutting the food, especially in birds of prey. In addition, he also serves on various technical services, such as building a nest as a " chisel ", when Gründeln as " Seihapparat " in food intake for dehulling of seeds or as a climbing aid. The bird in the world very different beak shape is closely related to function, especially for the type of food and method of food production. Example, there are curved and pointed beaks, Crossbills and Seihschnäbel.

In birds the beak is divided into upper and lower beak. The bony basis are the upper and lower jaws, which are coated with keratin. On the upper mandible horny sheath ( Rhamphoteca ) forms a convex back ( culmen ). The nostril is mostly at the base of the upper mandible, the only Kiwi on the tip of the beak.

The horny substance has a different surface profile. In some species, such as, for example, in the genus, the saw, to form a tooth-like strip, at the other, as in the floating duck slats that are used for filtration of food.

When misalignments of beaks or lack of wear and tear due to non- appropriate care and feeding of the Horn substance is no longer sufficient and rubbed it comes to extensions and / or curvature, which completely prevent the intake of food in an extreme form. For decorative birds here shortening or even a surgical beak correction is necessary. In the factory farming of hybrid chickens and turkeys beaks are cut to prevent cannibalism.

Pisces

For swordfish, sailfish and some other species the expression of the head is also referred to a sword-like tip ( rostrum ) as a beak.