Mammals are undoubtedly the best known and easily identifiable animals in the animal world, although it is impossible to speak of a certain number of species due to the extremely high variety of animals that fall under this heading. Mammals, including humans, share certain basic elements that have to do with the mode of reproduction, growth, feeding and in some cases the anatomical shape.
They can begin by describing mammals as vertebrates that have mammary glands (hence their name) through which the female feeds her young with her own milk, a process that does not occur among reptiles or birds. In addition, mammals have hair or skin unlike reptiles, fish and birds that have scales or feathers respectively. On the other hand, mammals live by consuming oxygen and producing carbon dioxide that is exhaled into the environment in which they inhabit. Mammals also share the respiratory system, the skin, the reproductive system, and the nervous system. In addition, mammals are characterized by being all warm-blooded animals unlike other animals.
Mammals are classified into three main types of animals: those that lay eggs such as the platypus, the marsupials (which are characterized by having a kind of bag to carry their young, such as the kangaroo or koala) and those that are born placenta (animals that develop to birth in the middle of the placenta, that is, most known mammals).
Among the mammals we can find those that are terrestrial, those that are aquatic (such as the whale), those of aerial locomotion (bats) or those that live in trees (such as the sloth). In addition, depending on the type of mammalian species, there are carnivorous mammals (those that live only by eating meat), herbivores (herbs) and omnivores (such as humans who consume a variety of foods).
