How were mammals able to differentiate in the Cenozoic Era?

During the Cenozoic Era, mammals underwent significant diversification due to various factors, including the extinction of dinosaurs that opened up ecological niches, climate changes that altered habitats, and the evolution of new feeding strategies and reproductive adaptations. This era saw the emergence of distinct mammalian orders, such as primates, cetaceans, and ungulates, as they adapted to different environments and lifestyles. Furthermore, the development of traits like specialized teeth and enhanced brain size facilitated their survival and ecological success. Overall, the Cenozoic Era was a critical period for mammalian evolution, leading to the vast diversity we see today.