Mammals, fascinating and diverse vertebrates, whose origin is unclear to us and is confused with the times in which dinosaurs and other reptiles lived.
The purpose of this book is to determine when they appeared, as well as to know the reptiles that gave them origin and the primitive groups of mammals that existed.
Likewise, we analyze the climatic and geological changes that have influenced the appearance and disappearance of the different groups of these tetrapods, until they reach the current monotremes, marsupials and placentas.
Finally, the mass extinctions that have occurred on planet Earth are mentioned and the origin of the human being, the current dominant mammal, is detailed. Likewise, the responsibility he has in his hands to preserve the environment that he himself has been responsible for destroying is indicated.