The mammals are vertebrates (they are supported by a bony skeleton) warm-blooded, characterized by udder (glands they use to feed their young), and their reproduction is almost always viviparous (the embryo is nourished by the blood his mother through the placenta). They then take care of their grandchildren (who often are born naked and blind) that they protect only, as a couple or as a group.
from "GUIDE VIGOT"
Descendant of reptiles that once dominated the land there are more than two hundred
million years ago, mammals inhabit today the entire planet in adapting to a wide
range of habitats, the rainforests to the ice poles, deserts Arid oceans, basements
to tops of trees.
More than 4600 species of mammals (compared with more than a million
species of insects) were zajeta throughout the world, including about 1125 in Africa.