Fossil Site Reveals How Mammals Thrived After the Death of the Dinosaurs
by Riley Black /Smithsonian.com
In central Colorado, at a place called Corral Bluffs, there lies an unusual graveyard. The ranks of the dead aren’t filled with people, but animals that lived 66 million years ago. Preserved in hardened concretions of stone lie the remains of turtles, crocodiles, and most of all, mammals that lived in this place during the first million years after the terrible impact that triggered the extinction of the dinosaurs. These animals form a part of our own evolutionary narrative—the story of how mammals went from scurrying around the feet of larger creatures to dominating the continents of the world, evolving into a variety of unique beings, including ourselves.
Mammals are not recent additions to the world that came after the time of the dinosaurs. The oldest mammals go back much further in time, and contrary to the standard story of shrew-like critters kept in check by monstrous reptiles, mammals thrived during Mesozoic era. The asteroid impact that felled the “terrible lizards” was also a portentous event for the mammals that had already been plying their own success for tens of millions of years.
The mammalian story is a complicated one.