Approximately the last 63 million years.
1At twenty-one minutes to midnight they vanish and the age of mammals begins.
2Hence the Tertiary period may be called "the age of mammals."
3Still higher, or more recent, are Cuvier and Brongniart's tertiary rocks, representing the age of mammals.
4Then came the Caenozoic age , or age of mammals, three million years, with strata thirty-one hundred feet thick.
5The age of mammals awaited the deepening and the enrichment of the soil and the stability of the earth's crust.
6They were the dominant land animals of their time, just as the quadrupeds were during the Age of Mammals.
7We think we're at the end of the Age of Mammals, and well into the Age of Managing the Ecology.
8From between the feet of stomping dinosaurs, ratty animals scurry about; cue an asteroid impact and the Age of Mammals begins.
9Thus, since vertebrates appeared, we have in succession the Age of Fishes, the Age of Amphibians, the Age of Reptiles, and the Age of Mammals.
Translations for age of mammals