Mammals are a class of vertebrate animals. To their features, besides feeding of cubs breast milk, live birth also belongs; they have also other distinctive features. In total there are about 4500 various types of representatives of this class.
Females of mammals during feeding of cubs have a milk. It is allocated from special glands which and are called: dairy. For newborn mammals it is natural food, but at each look it has the features. For example, in milk of a domestic cat of proteinaceous connections approximately in 10 times more, than cow milk. In zoology there is a special unit which is engaged in studying mammal. It is a teriologiya. As people raise babies milk too, and they belong to this class of living beings. Besides feeding, the person has also other features characteristic of all class of mammals. Their important feature which is especially strongly expressed at people is the developed forebrain and a cerebellum. At the majority of types of this class the brain is arranged difficult, has a set of crinkles and folds, and than their is more and than more difficult they are organized, especially the behavior of an animal can be various. The developed peripheral nervous system allows mammals to react to external irritants quickly. The binocular sight is also characteristic of them, that is the picture in a brain is formed on the basis of the image from both eyes, in difference, for example, from birds who see two eyes separately. Such features as breath by means of lungs and existence of four-chamber heart, are the general for mammals. Most of them has the indumentum necessary for maintenance of constant body temperature. These are warm-blooded types, and their average body temperature on a class is about 30 degrees. Exceptions are whales and hippopotamuses and also a human look which representatives protect themselves warm clothes. Mammals – a surprising class, its types are very different. Some of them fly, others live on the earth's surface, it is a lot of and such who carries out the most part of life underground. They are not too similar at each other. In total now among mammals there are 20 groups of the existing animals, slightly more than 10 more groups are died out. Hominids which people treat it is group of mammal primacies. Besides the modern person, Homo sapiens, Neanderthal men, pithecanthropi and some fossil types of people, for example, Australopithecuses treat hominids.