Because, 1. Mammals, which had been around since the Jurassic, diversified greatly throughout the Cenozoic Era. 2. We’re mammals, so that’s really important to us. read more
The Age of Reptiles ended with the Mesozoic era of the history of life on earth, some 60 million years ago. It was replaced by the Age of Mammals, which opened with the Cenozoic era and still goes on. read more