Some dinosaurs may have traits that allow them to endure cold winters during the Late Triassic and the early Jurassic period. It can explain how he came to be in control of the planet 135 million years later.
Analysis of rocky soils in the Junggar region of northwestern China, where dinosaur footprints have been found in the past, adds to the growing evidence that dinosaurs lived not only in green, tropical areas but also in cold, snowy forests.
Paul Olsen at Columbia University in New York and colleagues found signs that the region was in a state of flux during prehistoric reptiles. The sediment contains substantial particles common in the freezing lakes each year.
Dinosaur fossils have been found near poles, but models suggest that temperatures below freezing between 237 million and 174.1 million years ago have been challenged, so no one knew that reptiles lived in the cold.
The findings of Olsen’s team can explain how dinosaurs continued to dominate the Earth after the extinction of almost all terrestrial and marine creatures in the tropics.
The fossil record indicates that the middle and large reptiles abruptly disappeared at the end of the Triassic, when temperatures plummeted and a decade-long eruption clouded the air with sulfur. But giant dinosaurs in the middle reappeared almost everywhere after the extinction event, says Olsen, and the adaptation of cold dinosaurs to the cold probably explains why.
When temperatures plummeted during the end of the Triassic era, these dinosaurs were prepared for them, as they survived eating vegetation from the northern hemisphere and endured cold with feathers that served as heat, Olsen said. The dinosaurs then spread throughout the Jurassic world, replacing giant, unsealed reptiles.
Olsen said that evidence is the latest to suggest that our concept of dinosaurs needs to be rethought. “What our paper shows is that our view of the dinosaur world is really wrong,” he said. “Tropical dinosaurs are not on the edge. They are common. And, of course, dinosaurs are basically cold animals.”