Study reveals how dinosaurs thrived before an asteroid wiped them out

By Mark Waghorn via SWNS

Dinosaurs were thriving before an asteroid strike doomed them to extinction, according to new research.

In fact, it was their stability that made it harder for them to adapt quickly to the cataclysmic changes from the strike and their rapid extinction.

The findings provide the strongest evidence yet that the legendary beasts were struck down in their prime.

They were not in decline when the city-sized space rock crashed into what is now the Gulf of Mexico 66 million years ago.

Co-lead author Dr. Alfio Chiarenza of Vigo University in Spain said: “It seems the stable ecology of the last dinosaurs actually hindered their survival in the wake of the asteroid impact, which abruptly changed the ecological rules of the time.

“Conversely, some birds, mammals, crocodilians, and turtles had previously been better adapted to unstable and rapid shifts in their environments, which might have made them better able to survive when things suddenly went bad when the asteroid hit.”

An international team analyzed 1,600 fossils from North America dating back to a few million years before and after.

It enabled them to model the food chains and habitats of land-living and freshwater animals.

First author Dr. Jorge Garcia-Giron of Oulu University in Finland said: “Our study provides a compelling picture of the ecological structure, food webs and niches of the last dinosaur-dominated ecosystems of the Cretaceous period and the first mammal-dominated ecosystems after the asteroid hit.

“This helps us to understand one of the age-old mysteries of paleontology: why all the non-bird dinosaurs died, but birds and mammals endured.”

The idea dinosaurs were already teetering on the brink has been debated by paleontologists for years.

Last year, a study suggested they had been struggling to survive for 10 million years when the asteroid struck the final death blow.

It created the 125-mile-wide Chicxulub crater – unleashing climate-changing gases and killing three-quarters of life on the planet.

Non-bird dinosaurs, including T Rex and Triceratops, became extinct - whereas mammals and other species such as turtles and crocodiles survived.

The study in the journal Science Advances sheds fresh light on the mystery. It has been known for some time many small mammals lived alongside the dinosaurs.

But results show they were diversifying their diets, adapting to their environments and becoming more important components of ecosystems as the Cretaceous unfolded.

Meanwhile, the dinosaurs were entrenched in stable niches to which they were supremely well adapted.

Mammals didn’t just take advantage of the dinosaurs dying, the experts explain. They were creating their own advantages through diversifying.

They were occupying new ecological niches, evolving more varied diets and behaviors and enduring small shifts in climate by rapidly adapting.

These behaviors probably helped them to survive, as they were better able than the dinosaurs to cope with the radical and abrupt destruction caused by the asteroid.

Senior author Professor Steve Brusatte of Edinburgh University said: “Dinosaurs were going strong, with stable ecosystems, right until the asteroid suddenly killed them off.

“Meanwhile, mammals were diversifying their diets, ecologies and behaviors while dinosaurs were still alive.

"So it wasn’t simply that mammals took advantage of the dinosaurs dying, but they were making their own advantages, which ecologically preadapted them to survive the extinction and move into niches left vacant by the dead dinosaurs."

It backs the rival school of thought that dinosaurs were not on the way out - and may have continued to thrive.

They had weathered climate fluctuations throughout the 165 million years they roamed Earth, said Chiarenza.