Mammals inherit the Earth
Within ten million years of the impact, mammals go from shrew-sized to bear-sized and fill the empty world.
- When
- —
- Duration
- 10 million years
- Known to
- ± 1 million years
- Era
- Paleocene, Cenozoic
For 160 million years mammals had been held to small body sizes and narrow niches by an ecosystem run by dinosaurs. With that ceiling removed they expand explosively. Maximum body mass rises by orders of magnitude within a few million years, and the Paleocene fills with archaic groups — condylarths, pantodonts, taeniodonts, multituberculates — experimenting with herbivory, carnivory, digging and climbing. Most of these lineages are evolutionary dead ends that will not survive the Eocene, but the pattern is set: this is the beginning of the Age of Mammals.