Dinosaurs were at the top of their game when the asteroid wiped them out – that’s the finding of a new study which overturns scientists’ understanding of the dinos’ reign.
Scientists largely agree that an asteroid was responsible for the dinosaurs’ sudden disappearance 66 million years ago during the Cretaceous period. The space rock smashed into the Earth, causing earthquakes, wildfires, and a dust cloud that blocked out the Sun’s light for months or even years.
However, previous research suggested that dinosaurs may already have been in decline before this extinction event, due to long-term changes in the climate over the previous millions of years.
Now, analysis by a team of researchers in the UK has revealed that the dinos were likely doing just fine.
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The team focused their research on North America, where many Late Cretaceous dinosaurs have been found, including Tyrannosaurus rex and Triceratops.
Previous efforts to study the dinosaurs in this region have been hampered by an incomplete fossil record. During the Late Cretaceous, the east and west of the continent was separated by an inland sea. The western half had better conditions for forming fossils than the eastern half (due to an abundance of sediments from the newly-forming Rocky Mountains), resulting in more fossils being found in the west.
“Most of what we know about Late Cretaceous North American dinosaurs comes from an area smaller than one-third of the present-day continent, and yet we know that dinosaurs roamed all across North America, from Alaska to New Jersey and down to Mexico,” said Dr Philip Mannion, co-author of the study from University College London.
The team filled the gaps in the fossil record by using sophisticated computer models to simulate environmental conditions during the Late Cretaceous, such as temperature and rainfall. This allowed them to predict where in the continent the dinosaurs were likely to have survived as conditions changed.
They discovered that dinosaur-rich regions were likely more widespread at this time than previously thought – and that these were in places less likely to preserve fossils.
“The results of our study suggest that dinosaurs as a whole were adaptable animals, capable of coping with the environmental changes and climatic fluctuations that happened during the last few million years of the Late Cretaceous,” said Alessandro Chiarenza, lead researcher and PhD student at Imperial College London. “Climate change over prolonged time scales did not cause a long-term decline of dinosaurs through the last stages of this period.”