According to scientists, Dinosaurs were the dominant land animal because they were more adapted to cold temperatures. A mass extinction took place 202 million years ago at the end the Triassic. The dinosaurs overtook the large reptiles which had dominated terrestrial ecosystems. How did they survive? Paul Olsen, a paleontologist and his colleagues claim that it was possible due to the existence of groups of dinosaurs that were adapted for living in cold environments.
It was hot and humid in the Jurassic and Triassic worlds. All the lands that emerged were located on Pangea, a continent which broke up during the Jurassic, when the Atlantic Ocean crack opened. The atmospheric concentrations of carbon dioxide, CO2, were approximately 2,000 parts per millions, as opposed to the current 421. Although there is no evidence of polar ice caps, there was evidence of deciduous forest at the poles. Temperatures in the tropics were 60 degrees. Some climate models, however, suggest that high latitudes were cool during periods of little sunlight.
Scientists aren't sure what exactly happened 202 millions years ago. Olsen and his colleagues start with the possibility that the great extinction was caused either by a planetary collision, such as the one that killed the dinosaurs 66 millions years ago, or by a series large-scale volcanic eruptions. They claim that the sulfur from the volcanoes caused repeated global winters, in which the tropics may have even frozen. Three quarters of all terrestrial and marine species went extinct, along with all large reptiles. Some primitive mammals and burrowing turtles survived, and the reign began of the dinosaurs.
Researchers have presented the first evidence that Triassic dinosaurs thrived in cold environments. They found footprints of these animals next rock fragments that could only be deposited by ice from China's Junggar Basin. This was 202,000,000 years ago. At approximately 71 degrees North. The northern dinosaurs were able to survive in the colder climates that developed from massive volcanic eruptions.
"Dinosaurs existed during the Triassic and were not visible to the radar. His final mastery was simple. They were cold-adapted animals. Olsen explains that they were prepared for cold weather, while other animals weren't. They were born in temperate latitudes 231 million years ago, but they reached north to Pangea 214 millions years ago. According to the authors, feathers may have played a significant role in dinosaurs' cold adaptation.
Recent evidence has been gathered by paleontologists that primitive feathers were present in many dinosaurs, including the tyrannosaurus. Olsen and his coworkers believe that they were used for thermal protection, and that birds can fly with them.
"Extreme winter events in volcanic eruptions may have brought freezing temperatures into the tropics. This is where large numbers of the extinctions occurred of naked, featherless vertebrates. Dennis Kent, a geologist and one of the co-authors of the study, said that feathered friends did well in cooler temperatures at higher altitudes.