Mammals
Contrary to the view held by scientists that the rise of mammals coincides with the extinction of dinosaurs, a new study has revealed that mammals began to flourish well before the end of the dinosaur age.

Under the study, the researchers, from the Universities of Southampton and Chicago, analysed hundreds of fossil teeth of mammals.

The findings of the study showed that those with varied diets began to adapt 10 to 20 million years before the extinction of the dinosaurs.

Researchers said that the present study is in contrast to the traditional view held by scientists that the extinction of dinosaurs around 66 million years ago paved the way for mammals to evolve and thrive.

The report was published in the Proceedings of the Royal Society B.

Mass extinction of dinosaurs

The study revealed that the discovery of more and more early mammal fossils, including some hoofed animal predecessors the size of dogs, in the recent years shows that mammals had begun to flourish well and were present in greater diversity before the extinction of the dinosaurs than first thought.

Co-author Elis Newham, a PhD student at the University of Southampton, said,

“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.”

Also, since the mammals were flourishing before the extinction of the dinosaurs, it also shows that instead of benefitting from the demise of dinosaurs, mammals also appeared to have suffered greatly from the asteroid impact which wiped out more than half of all life on Earth.

Lead author David Grossnickle, a PHD candidate at the University of Chicago, said the study was particularly important at this point in light of the mass extinction the earth was currently undergoing.

He said,

“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.”

Dinosaurs were already declining

Another recent study had suggested that the dinosaurs were already in decline 50 million years before the asteroid strike that finally wiped them out.

The asteroid impact is commonly thought to have paved the way for mammals to take over. However, the new study suggested that mammalian supremacy might have occurred eventually, without the impact of the asteroid.

Co-author Prof Mike Benton of Bristol University, told BBC News,

“World climates were getting cooler all the time. Dinosaurs rely on quite warm climates and mammals are better adapted to the cold.

“So there might have been a switch over in any case without the asteroid impact.”

Dr Manabu Sakamoto, a palaeontologist from the University of Reading, who led the research, said,

“We were not expecting this result.”

“Even though they were wiped out ultimately by the impact of the asteroid, they were actually already on their way out around 50 million years before the asteroid hit.”