Why giraffes will become short again?

The evolution of mammals is explored through their adaptation to changing gravitational forces, leading to a gradual reduction in size over time. Initially, larger mammals like elephants and rhinos reached their peak sizes in the past, while giraffes are currently at their peak and will likely decrease in size in the future. The book acknowledges the contributions of notable thinkers such as Giordano Bruno and Bertrand Russell, emphasizing the ongoing process of mammalian evolution and the implications of size reduction across species.