# T. rex's Warm-Blooded Nature Revealed Through Tooth Analysis Dental thermometry shows T. rex maintained elephant-like body temperature. - **Source:** [Ars Technica - All content](https://brifing.si/source/b728770c-8dda-457a-8986-84879c9fc42c) - **Published:** 2026-09-20 - **Topic:** [Business](https://brifing.si/c/business) - **Original article:** - **On Brifing:** https://brifing.si/s/3ef96760-fd05-4fb6-bf74-d81253b5cefc ## Shifting perceptions of T. rex The Tyrannosaurus rex was long depicted as a slow, cold-blooded reptile requiring external heat sources. This view changed dramatically with discoveries showing it as an active predator, more akin to modern birds. The Jurassic Park portrayal reflected this updated understanding. However, the metabolic mechanism enabling such activity remained unresolved until now. ## Breakthrough measurement technique UCLA geochemists Randon J. Flores and Robert A. Eagle developed a method to measure body temperature through fossilized teeth. Their dental thermometry approach analyzed isotopic compositions in tooth enamel that record biological temperatures. This provides direct evidence rather than relying on indirect indicators like bone structure or growth rates used in previous studies. ## Elephant-like thermoregulation The team's measurements revealed a T. rex body temperature of approximately 36°C. This matches the internal temperature of modern elephants, suggesting similar metabolic strategies. The finding places T. rex firmly among endothermic species that maintain stable internal temperatures independent of their environment. ## Resolving long-standing debates Paleontologists have disputed dinosaur physiology for decades, with conflicting evidence about their thermoregulation. Some studies suggested endothermy based on rapid growth rates, while others proposed varied thermal strategies across lineages. The direct temperature measurement provides crucial evidence to settle these debates about the largest terrestrial predators. ## Methodological significance The dental thermometry technique represents a major advancement in paleontology. Unlike previous approaches that inferred metabolism indirectly, this method measures actual biological temperatures preserved in fossils. It opens new possibilities for studying other extinct species' physiologies with similar precision. ## Evolutionary implications The findings suggest warm-bloodedness may have been more widespread among dinosaurs than previously thought. This challenges traditional classifications that strictly separate reptiles from endothermic species. The results also support the evolutionary link between certain dinosaurs and modern birds. ## Future research directions Scientists can now apply this technique to other dinosaur species to map the evolution of thermoregulation. Comparative studies across different periods and environments may reveal how metabolic strategies contributed to dinosaurs' dominance. The method could also help understand physiological adaptations to climate changes. ## Redefining dinosaur biology This discovery fundamentally alters our understanding of how T. rex and related species functioned. The evidence of elephant-like metabolism explains their predatory capabilities and supports theories about their active lifestyles. It represents a paradigm shift in reconstructing the biology of extinct megafauna. ## Sources covering this story - https://arstechnica.com/science/2026/09/t-rex-teeth-indicate-it-ran-as-warm-as-an-elephant/ — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._