For a long time, it was believed that dinosaurs were already in a state of decline before the asteroid impact. However, a new study published in Science dramatically changes this view. The new data suggests that dinosaurs were thriving right up until the fateful strike — it was the cosmic catastrophe, not internal problems, that led to their extinction.

Illustration of Cretaceous period dinosaurs, 66 million years ago, when a huge meteorite struck Earth.
Artwork by AI Copilot.

A team of scientists led by Dr. Andrew Flynn from the University of New Mexico conducted a thorough analysis of rock formations in the San Juan Basin. The area known as the Naashoibito Member contains some of the youngest dinosaur fossils in the world. Using two independent methods — argon isotope analysis and studies of the magnetic polarity of the rocks — the researchers were able to establish a more precise age for these deposits.

The result was sensational: the last dinosaurs of North America lived here just a few hundred thousand years before the asteroid strike. In geological terms, this is an incredibly short period of time.

Prosperity, not decline

The key conclusion of the study was that dinosaurs not only survived but actively thrived. Fossil analysis showed that even in the final millions of years of their existence, they were extremely diverse and well-adapted.

“There is no single North American dinosaur fauna that would make them prone to extinction,” Flynn assured. Instead, there were separate communities that were well adapted to their regions. The north of the continent was home to the familiar triceratops and edmontosaurus, while the south, including New Mexico, was home to giant sauropods.

At the end of the Cretaceous period, dinosaurs ruled the Earth, enjoying their heyday.
Illustration: Unsplash

Professor Steve Brusatte from the University of Edinburgh enthusiastically talks about one of these giants: “Alamosaurus was nearly 30 meters long and weighed more than a Boeing 737. There is no evidence that these dinosaurs were undergoing anything unusual or were in a state of prolonged decline.”

Why did the myth of decline arise?

The researchers offer a logical explanation for this mistake. Dr. Flynn believes it may be related to the nature of the geological record. At the end of the Cretaceous period, there were fewer exposed rocks available for study than before. This creates an “insufficient evidence” effect: fewer rocks — fewer fossils — the illusion of decline. In reality, when looking at specific rich sites like those in New Mexico, the picture is quite different.

“As far as we can tell, it seems there is no reason they should have gone extinct, other than the asteroid impact,” Flynn concludes.

This work has received positive feedback from the scientific community. Professor Michael Benton from the University of Bristol, who was not involved in the study, called the new evidence “very interesting.” At the same time, he noted that the question of global dinosaur decline remains debatable, as the new study focuses on only one specific location.

However, one thing is now clear: at least in some regions of the planet, dinosaurs met their end at the peak of their evolution, unaware of the inevitable threat from space.

Earlier, we reported on how cockroaches survived after a meteorite strike.