The Knowledge in a Dino’s Smile

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In life, a T. rex’s enamel had been fearsome. Arguably the majestic carnivore’s most dear weapon. But 66 million years after the king of dinosaurs exited the Mesozoic scene, its fossilized, banana-size flesh rippers are discovering a brand new function. Fossilized T. rex enamel—together with gnashers from different dinosaur species—are yielding chemical clues that may assist researchers reconstruct Earth’s historic local weather.

Scientists in Germany have divulged the atmospheric secrets and techniques locked inside fossil dino enamel by analyzing oxygen isotopes in historic dental enamel. Reporting their findings within the Proceedings of the National Academy of Sciences, researchers on the University of Göttingen, Johannes Gutenberg University Mainz, and Ruhr University Bochum counsel the air that T. rex breathed was a lot richer in carbon dioxide than our current-day ambiance. Oxygen isotope ranges in dino enamel from Europe, North America, and Africa additionally counsel that the sum of Earth’s flowers was twice as photosynthetically lively because the planet’s greenery is now. So, in the course of the Mesozoic Era, from 252 million to 66 million years in the past, the biosphere and the ambiance had been very totally different than immediately.

Further particulars of the climatic reconstruction counsel that the Late Jurassic (about 150 million years in the past) was marked by a focus of atmospheric carbon dioxide that was 4 occasions greater than the degrees current on Earth previous to the nineteenth century’s Industrial Revolution, when people beginning pumping the greenhouse gasses into the air. The scientists additionally discovered isotopic echoes of mass volcanic eruptions across the finish of the Cretaceous interval (about 66 million years in the past).

The dinosaur tooth isotopic evaluation allowed researchers to look additional again than ever into Earth’s historic ambiance—a significant breakthrough within the discipline of paleoclimatology. Older, much less dependable, strategies of historic local weather reconstruction relied on measuring soil carbonates and marine local weather proxies. This was the primary time scientists used fossils from terrestrial vertebrates to glimpse previous climates.

“Our method provides us with completely new insights into the Earth’s past,” stated lead writer Dingsu Feng of the Geochemistry and Isotope Geology Department of the University of Göttingen in a statement. “We now have the possibility to use fossilized tooth enamel to study the composition of the atmosphere of the early Earth and the productivity of terrestrial and marine vegetation back then. This is crucial for our understanding of long-term climate dynamics.” 

Lead picture: Teeth from dinosaur fossils, akin to this Tyrannosaurus rex found at Murray Ranch in Montana, retain signatures of the ambiance that existed when the creatures roamed the Earth. Credit: © Naturalis Biodiversity Center.

• Bob Grant

  Posted on August 8, 2025

  Bob Grant is the deputy editor at Nautilus.