Mammals

Earth has a large variety of animals living on it. Mammals are among the most intelligent of all living creatures. Scientists have identified more than 5,000 species of living mammals, roughly one-fifth of which are known to be threatened or extinct. Mammals come in all sorts of shapes and sizes and are found in every major habitat around the world. From whales and dolphins in the sea to elephants and primates on land, mammals have found homes in a variety of places, including in trees and in the air.