About 66 million years ago, the largest and strongest animal species the earth has ever known came to an end. A devastating meteorite impact eventually killed the dinosaurs. But they’ve been struggling for a long time.
For millions of years, they struggled to survive, according to new research on the evolutionary trends of six major dinosaur species, including the Tyrannosaurus and the Triceratops. “We’ve looked at dinosaurs throughout the Cretaceous Period, ranging from 160 to 66 million years ago,” said study leader Fabien Condamine.
The problems started 10 million years before the fatal meteorite impact. “About 76 million years ago, the dinosaurs had a sudden decline,” Condamine says. “Their extinction rate increased and in some cases the rate of emergence of new species decreased.”
The main cause was the falling temperature on the planet, the researchers explain. It was only 7 degrees Celsius at that time, while dinosaurs need much higher temperatures. Plant eaters in particular had a hard time, making the entire ecosystem unstable and other dinosaur species also became extinct.
The meteorite was the final blow. “This was a key moment in the evolution of life,” Condamine concludes. “The world has been dominated by dinosaurs for over 160 million years. As they declined, other groups began to become more dominant, including mammals.”
