It has long been believed the asteroid that wiped out the dinosaurs spared much of the mammal population, but new research suggests that was not the case.

It has long been believed the asteroid that wiped out the dinosaurs 66 million years ago spared much of the mammal population, but new research suggests that was not the case. 
Scientists from the Milner Centre for Evolution at the University of Bath recently determined that more than 90 percent of the mammal species became extinct, but they also rebounded quickly. 
The study involved a large-scale review of all known North American mammal species in the two million years leading up to the asteroid strike and in the roughly 300,000 years following. 
According to Nick Longrich, the study’s lead author, that larger than typical data set, “…shows that the mammals were hit harder than most groups of animals, such as lizards, turtles, crocodilians, but they proved to be far more adaptable in the aftermath. It wasn’t low extinction rates, but the ability to recover and adapt in the aftermath that led the mammals to take over.”