It is widely believed that an asteroid strike about 66 million years ago wiped out dinosaurs on Earth. But the giant beasts’ population was already in decline more than 50 million years before the space rock hit the Gulf of Mexico. According to a new study published in the journal Proceedings of the National Academy of Sciences, the asteroid may have been the final nail in the coffin.
Sauropods were declining the fastest
The new study has further fueled the debate on how the giant animals were doing before a space rock slammed the Earth, producing tons of dust, blackening out the Sun, and driving about 75% of plants and animals to extinction. Researchers led by Dr Manabu Sakamoto of the University of Reading found that the creatures were in a long-term decline as they couldn’t adopt to the changing environment on Earth.
Paleontologists analyzed fossils of dinosaurs from the point they first emerged on Earth 231 million years ago to the point they went extinct. They thrived at an explosive rate in the beginning, but things started changing about 160 million years ago. The number of dinosaur species started declining 120 million years ago. Researchers found that the long-necked sauropods were declining the fastest. In contrast, theropods were undergoing a slow decline.
Why were dinosaurs in decline?
It is certainly true that the asteroid strike wiped them out, but they were already on their way out 50 million years before the asteroid hit. Scientists believe that the dinosaurs’ long-term decline had rendered them even more susceptible to the catastrophe triggered by the space rock. Perhaps they would have fared much better if they were reigning strong.
So, why was the dinosaur population declining? Paleontologists say it’s because they couldn’t cope with the way our planet’s environment was changing. About 230 million years ago, conditions were perfect for dinos, lush and warm from pole to equator. But then the climate cooled, continents broke up, sea levels shifted, and more volcanoes got active. It would have left the dinos in fragmented habitats where they had limited opportunities to reproduce.