In a new study from the Chinese Academy of Sciences (NIGPAS) and Columbia University, researchers set out to explain how dinosaurs lived through the Triassic extinction event, which killed many other animals. The results of the study suggest that feathers played a major role in helping the dinosaurs survive by giving them the insulation they needed to endure freezing temperatures.
Approximately 202 million years ago, the Triassic-Jurassic Extinction wiped out the large reptiles that ruled the planet. During the same time period, dinosaurs not only survived, but thrived and rose to dominance. The experts report that dinosaurs were well-adapted to the cold in a way that other species were not.
“Dinosaurs were there during the Triassic under the radar all the time. The key to their eventual dominance was very simple. They were fundamentally cold-adapted animals. When it got cold everywhere, they were ready, and other animals weren’t,” explained Paul Olsen, a geologist at Columbia University’s Lamont-Doherty Earth Observatory.
The researchers found physical evidence of dinosaur footprints from the Junggar Basin in northwestern China. This region was located well above the Arctic Circle. The footprints indicated that dinosaurs were present along the shoreline.
In addition, the analysis of deep lake deposits produced a large number of pebbles up to about 1.5 centimeters in diameter which turned out to be ice-rafted debris (IRD). This type of debris is created when ice abuts a coastal landmass and incorporates bits of underlying rock as it freezes.
The researchers said the pebbles were likely picked up during winter, when lake waters froze along pebbly shorelines. In warmer weather, chunks of ice carried the pebbles offshore and eventually dropped them.
The discovery of IRD confirmed the theory that dinosaurs were capable of living in freezing conditions. “This shows that these areas froze regularly and the dinosaurs did just fine,” said study co-author Dennis Kent.
Using a “phylogenetic bracket analysis,” the experts concluded that dinosaurs were primitively insulated with feathers. The insulation from these feathers allowed the creatures to adapt to cold polar conditions.
After the Triassic extinction event, dinosaurs rapidly increased in size, expanded their range, and nearly doubled their overall population. They were the most dominant animals in Earth for the next 135 million years.
The study is published in the journal Science Advances.