Overview
- The peer‑reviewed Science Advances paper published on September 16, 2026 reports clumped‑isotope measurements from three Tyrannosaurus rex teeth that yield a mean body temperature of 36.3 ± 2.5°C.
- Researchers used clumped‑isotope paleothermometry on tooth enamel, a method that reads how rare carbon and oxygen isotopes bonded as enamel formed to infer the animal’s internal temperature.
- Five crocodilian teeth from the same Hell Creek site produced cooler values around 30.9°C, which the team used as a geological and diagenetic control to support a biological temperature signal for T. rex.
- A mammal‑like body temperature implies higher metabolic rates, greater food needs, more sustained activity, and the ability to live in cooler, higher‑latitude regions according to the authors’ paleoclimate models.
- The study relied on a decade of lab refinements that cut required enamel sampling by about 90 percent so museums would permit testing, but authors and outside experts stress the result applies to the sampled individuals and call for broader sampling to map variation across dinosaurs.