Mammals
Mammals, or beasts, enlisting 4475 species, is the most widely known group of the vertebrates. Females of these animals feed the babies with their milk lactated by mammary glands. Most beasts deliver living babies and their body is covered with hair. The most widely spread mammals live overland but also they could come to water and even go up to the sky. They achieved success mainly due to the capability to keep constantly high body’s temperature irregardless of the environment conditions. Besides beasts have flexible means and plastic behavior allowing them to take into consideration the previous experience. Some mammals, especially apes, form complicated communities. Unfortunately all main mammals groups have threatened species and some of them are in a particularly dangerous situation. The apes are in the most complicated situation, mainly it is the aftermath of ruining forest landscapes. The Australian marsupials will be on the verge of extinction soon because of attacks by aggressive introduced species.
