A new chemical analysis of Tyrannosaurus rex teeth suggests the giant predator maintained a body temperature close to that of humans, strengthening the case that it was warm-blooded rather than a sluggish reptile dependent on outside heat.
Researchers analyzed enamel from three T. rex teeth found in Montana and calculated an average body temperature of about 36.3 degrees Celsius, or 97.3 Fahrenheit. The work, published in Science Advances, used the relationship between carbon and oxygen isotopes preserved as tooth enamel formed.
The team compared the dinosaur teeth with crocodilian teeth from the same geological formation. The crocodilians registered substantially lower temperatures, providing an important control for the method.
Warm-bloodedness would have given T. rex greater stamina and allowed it to remain active across a wider range of climates, but it would also have required considerably more food. Researchers caution that the result applies specifically to T. rex and should not automatically be extended to every dinosaur.
Source: Reuters reporting on research published in Science Advances, Sept. 16, 2026.
