Overview
- The peer‑reviewed paper published Sept. 16 in Science Advances reports an average body temperature of about 36°C (97°F) from clumped‑isotope measurements on three Tyrannosaurus rex teeth.
- Researchers used a refined clumped‑isotope method that reads rare carbon‑oxygen bonds in tooth enamel to infer the temperature at which the enamel formed, with enamel chosen because it resists chemical change after burial.
- Two of the sampled teeth came from the near‑complete T. rex known as Thomas and the Natural History Museum of Los Angeles County approved limited, small‑scale destructive sampling after the lab cut required material by roughly 90 percent.
- Five contemporaneous crocodilian teeth from the same Hell Creek site yielded cooler temperatures (~31°C/88°F), which the team used as a geological control to show the warm T. rex signal was biological rather than a post‑burial artifact.
- The result supports warm‑blooded physiology for the measured individuals and, with paleoclimate models, suggests a broad North American range for T. rex, but authors stress the sample is small and call for wider enamel testing across species, sizes and regions.