The main characteristics of mammals

The main characteristics of mammals are as follows:

First, the characteristics:

Mammals have hair on their body surface, which is generally divided into five parts: neck, trunk, limbs and tail. Breathe with the lungs; A warm-blooded animal with a constant body temperature; The brain is big and developed; Breastfeeding; Viviparous

Breastfeeding and viviparous are the most striking features of mammals. The embryo develops in the mother, and the mother beast directly gives birth to the fetus. The mother beast has mammary glands and can secrete milk to feed the fetus. Mammalian teeth are divided into incisors and canines.

Second, what is a mammal:

A class of vertebrates, commonly known as mammals. Most mammals are vertebrates, with hairy body, fast movement, constant temperature viviparous and diaphragmatic body. They are the highest animal group with the most complicated body structure and functional behavior among vertebrates, so they are named because they can breastfeed their young through mammary glands.

Mammals can be divided into protozoa, juveniles and metazoa. Mammals are distributed all over the world, living on land, underground, water and air. There are three types of nutrition: herbivorous, carnivorous and omnivorous.

Classification and origin of mammals;

A, the classification of mammals:

Mammals belong to the animal kingdom, chordates, vertebrates and mammals. It is estimated that there are 5400 species of mammals in the industry, which are divided into 29 orders 1200 genera.

Mammals are divided into two subclasses: protomammals (including oviparous monotremes) and mammals (including placental mammals and oviparous marsupials).

Most mammals (including 6 largest orders) belong to placental mammals. Among them, the largest three orders are rodents, Chiroptera and Carniptera. Rodents include rodents, Chiroptera includes bats, and shrews include shrews, moles and rodents.

Second, the origin:

Mammals evolved from reptiles. Mammals have made great progress because of their unique advantages of constant temperature and warm and humid climate conditions in Mesozoic. Including the evolution of long-nosed, odd-hoofed, cloven-hoofed, carnivorous, primate and angiosperm, as well as the famous Shanwang biota.