Culture

Study: Dinosaurs Thrived Before Asteroid Impact

APR 10 2025·Updated APR 12 2025

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The Facts

A comprehensive study analyzing over 8,000 North American dinosaur fossils from 84 to 66 million years ago has revealed that the apparent decline in dinosaur populations before the asteroid impact was likely due to poor fossil preservation rather than actual population decrease.
Livescience.Com
The Times of India
Nature
Researchers from University College London, led by Dr. Christopher Dean, employed occupancy modeling techniques to estimate dinosaur presence across North America. They divided the continent into a grid and considered factors such as geology, geography, and climate at the time.
ScienceDaily
Cell
The study focused on four major dinosaur groups: Ankylosauridae (armored herbivores), Ceratopsidae (horned dinosaurs), Hadrosauridae (duck-billed dinosaurs), and Tyrannosauridae (carnivores), finding that their habitat occupation remained stable throughout the period.
ScienceDaily
Gadgets 360
Geological changes, including the retreat of the Western Interior Seaway and the rise of the Rocky Mountains around 75 million years ago, significantly impacted fossil preservation and accessibility, creating a misleading impression of dinosaur decline.
Livescience.Com
Cell
Ceratopsian dinosaurs, including Triceratops, showed higher detection rates in later periods due to their preference for open plains, which became the predominant preserved environment following the retreat of inland seas.
ScienceDaily
UCL News
The research suggests that without the asteroid impact, dinosaurs might have continued to coexist with mammals, lizards, and their surviving descendants, the birds, as they showed no significant signs of population decline.
The Times of India
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The Spin

Narrative A

The fossil record has been misinterpreted for decades, leading to incorrect conclusions about dinosaur decline. The apparent decrease in dinosaur populations is actually due to geological processes that limited fossil preservation, not a real biological decline. These magnificent creatures were thriving right up until the asteroid struck.

Discover Magazine

Narrative B

While the immediate pre-extinction period might show stable populations, the overall evolutionary trajectory of dinosaurs shows a concerning pattern. The rate of new species emergence was declining over the 175 million years of dinosaur existence, with more species going extinct than evolving, indicating a broader, long-term decline in dinosaur diversity. The mystery of the complex downfall of the dinosaurs is not fully settled.

New Scientist