Why Dinosaurs Were Thriving Before the Asteroid: Uncovering the Truth Behind Their Extinction

Scientists are rethinking what we know about dinosaurs and their fate before a massive asteroid struck Earth 66 million years ago. Contrary to the long-held belief that dinosaurs were on a decline, a new study suggests this idea may stem from misleading fossil evidence.

For decades, it was commonly thought that dinosaurs were disappearing and diversifying less as they approached the end of the Cretaceous period. Some experts argued this indicated that extinction was already on the horizon. But this theory has faced challenges. Dr. Chris Dean from University College London explains that the debate has lasted for over 30 years. Researchers have now analyzed nearly 18 million years of fossil data and made an intriguing discovery.

Their research, published in Current Biology, examined about 8,000 fossils from two critical time periods: the Campanian (83.6 to 72.1 million years ago) and the Maastrichtian (72.1 to 66 million years ago). They focused on various dinosaur families, including Ankylosauridae, Ceratopsidae, Hadrosauridae, and Tyrannosauridae.

Initial findings suggested that dinosaur diversity peaked around 76 million years ago, then decreased leading up to the asteroid impact. However, the researchers found no evidence of environmental conditions that would explain this decline. These dinosaurs were thriving in many areas, and they were not as close to extinction as previously thought.

Dr. Alfio Alessandro Chiarenza, another researcher in the study, pointed out that geological conditions during the Maastrichtian might not have favored fossilization. For instance, changes like the retreat of the Western Interior Seaway and the rise of the Rocky Mountains around 75 million years ago may have made it harder for fossils to form. Their study highlights how half of the known fossils from this time emerge from North America, which is crucial since the findings may impact our understanding of dinosaur history globally.

Interestingly, the researchers found that certain species, like Ceratopsians (including the well-known Triceratops), were more commonly preserved than duck-billed Hadrosaurians. This might be due to their habitats, as Ceratopsians occupied plains, while Hadrosaurians thrived near rivers, a setting prone to fluctuating river flows that could impact fossil preservation.

The takeaway from this research is that dinosaurs were likely not doomed to extinction before the asteroid’s impact. They were surviving well until that catastrophic event occurred. If it weren’t for the asteroid, dinosaurs might still roam alongside mammals and birds today.

As science continues to evolve, so too will our understanding of history’s great creatures. If you want to dive deeper into this fascinating world, check out the full study in Current Biology here.

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