Mammals ‘rose to power’ long before the dinosaurs died, study says

Mammals may have been around at the same time as the dinosaurs, but the commonly held view says that they were mostly rodents that scurried around the feet of the thunder lizards.

However, according to a new study, there were many large mammals coexisting at the same time as dinosaurs and a high amount of diversity among those mammals.

“The traditional view is that mammals were suppressed by the dinosaurs’ success, and that they didn’t really take off until after the dinosaurs went extinct. This study shows that therian mammals, the ancestors of most modern mammals, were already diversifying before the dinosaurs died out,” lead author David Grossnickle, a PhD candidate at the University of Chicago, told redOrbit in a statement.

Published in the Proceedings of the Royal Society B, the new study is based on the investigation of the fossilized molars of hundreds of early mammals. The study team discovered the mammals that existed before dinosaurs’ extinction had widely diverse tooth shapes, which means they had broadly diverse diets. These various diets proved crucial to understanding the study’s other main finding: Many mammal species went extinct alongside the dinosaurs.

Early mammals struggled before they thrived

While mammals appear to have diversified earlier than what past projections have shown, the mass extinction wasn’t the opportunity mammals were waiting for to take over the Earth. In fact, early mammals were struck by a simultaneous and selective extinction. Mammals that could live off of a wide range of foods appear to be better suited to survive, but some mammals with specific diets were wiped out.

“I fully expected to see more diverse mammals immediately after the extinction,” Grossnickle said. “I wasn’t expecting to see any sort of drop. It didn’t match the traditional view that after the extinction, mammals hit the ground running. It’s part of the reason why I went back to study it further–it seemed wrong.”

The University of Chicago scientist said flowering plants might have offered new food sources for the mammals.

“And, if the plants co-evolved with new insects to pollinate them, the insects could have also been a food source for early mammals,” Grossnickle pointed out.

He added that the study is relevant in light of the today’s extinctions and threatened populations.

“The types of survivors that made it across the mass extinction 66 million years ago, mostly generalists, might be indicative of what will survive in the next hundred years, the next thousand,” he said.

—–

Image credit:  Nobu Tamura

The post Mammals ‘rose to power’ long before the dinosaurs died, study says appeared first on Redorbit.

redOrbit.com
offers Science, Space, Technology, Health news, videos, images and reference information. For the latest science news, space news, technology news, health news visit redOrbit.com frequently. Learn something new every day.”