Bird

Birds are included in the Aves class and consist of approximately 9,000 species. Birds have no teeth and only have tails, but these animals share similar features with reptiles. For example, the presence of foot scales, hard beaks, and including ovipar animals that produce hard-shelled amniotic eggs.

In general, classifying birds is based on the type of beak and legs. However, there are also classified birds based on their habitat and behavior. In this case known to some groups of birds. For example, groups of hunter birds (birds with dipped beaks and sharp claws); beach birds (birds with slender, sharp beaks and long legs); peluk birds (birds with beak like chisels with type of grasping feet); water birds (birds with finger-finned and wide beaks); penguins (birds that modify wings like oars); and birds of prey (birds that have the type of feet to perch).

Birds are the only modern animal that has feathers on most of its body. There are two types of feathers, namely flying feathers and down feathers. Feather down is useful to block the loss of body heat. This is important because birds include homoterm animals, animals that maintain constant and relatively high temperatures that remain active even in cold weather.

Based on the anatomical arrangement, the feathers can be divided into three kinds, namely as follows.
Plumae, is a feather that gives the basic shape of the body that is on the wings and tail. This type of fur serves to fly.
Plumuae, is a feather contained in young birds and in birds that are incubating eggs. This type of fur serves as an insulator (for example, to temperature).
Filoplumae, is a hairy hair. The fur grows throughout the body surface. This type of feather functions as a sensor.
The bird's body is not completely overgrown by feathers. Part of the surface of the skin that is not hairy is called apteria, while the fur is called pterilae. The shape and structure of the bird's body is often associated with its ability to fly. This is so related to having a very light hollow bone. The beak can replace the jaw function. Chest bone size is more appropriate to its function as a balancing body. On the breastbone there is a strong muscle to fly.

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