Scientists reveal that dinosaurs were flourishing at the time of their extinction, while mammals adapted to survive the asteroid impact.

Recent research challenges the long-held belief that dinosaurs were in decline before their sudden extinction, revealing that they were actually thriving up until the catastrophic asteroid strike 66 million years ago.

An international team of palaeontologists and ecologists conducted a groundbreaking study based on 1,600 fossil records from North America. They discovered that dinosaurs, including well-known species like Tyrannosaurus rex and Triceratops, were far from in decline. The study suggests that these creatures dominated their ecosystems right up until the asteroid impact, providing the most robust evidence to date of their prosperity.

Scientists have long debated why non-avian dinosaurs perished, while other species, including mammals, survived. The new study proposes that the mammals which endured the extinction event may have had an advantage in adapting to rapid environmental changes. Unlike the dinosaurs, which were highly specialised and adapted to stable ecosystems, mammals were already diversifying their diets and behaviours, allowing them to survive in the wake of the disaster.

As the Cretaceous period drew to a close, small mammals were becoming more important components of ecosystems, evolving to exploit a wider range of food sources. These adaptive behaviours may have given them the resilience needed to endure the asteroid impact’s drastic ecological changes. In contrast, the dinosaurs, with their specialised diets and behaviours, were ill-prepared for the abrupt disruption of their environment.

Lead author Alfio Alessandro Chiarenza from the University of Vigo explained, “The stable ecology that benefitted dinosaurs during their reign actually hindered their survival after the asteroid impact. Meanwhile, species like birds, mammals, and turtles were already better suited to environmental shifts, making them more capable of surviving the sudden and violent changes caused by the asteroid.”

Senior author Professor Steve Brusatte from the University of Edinburgh further elaborated, “Dinosaurs were thriving until the asteroid struck, but mammals had already begun diversifying their behaviours and ecologies. They didn’t simply take advantage of the dinosaurs’ extinction – their evolutionary adaptations prepared them to fill the ecological gaps left behind.”

The study provides new insights into how the surviving mammals were not just lucky but were actively shaping their future survival by adapting to their changing environments long before the asteroid’s impact.