T. Rex Body Temperature Matched That of Modern Elephants, Study Finds

For decades, the public perception of Tyrannosaurus rex was shaped by its depiction as a slow-moving, cold-blooded reptile that required basking in the sun to become active. Over time, scientific understanding evolved, with the dinosaur increasingly portrayed as a vigorous, bird-like creature similar to the one seen in Jurassic Park. However, a key question remained unresolved: did the T. rex possess the warm-blooded physiology necessary to sustain such activity?

New research suggests we may now have a clearer answer. Randon J. Flores and Robert A. Eagle, geochemists at the University of California, Los Angeles, led a team that determined the dinosaur’s body temperature by examining its teeth. Their analysis indicated a stable internal temperature of approximately 36°C, which is nearly identical to the body temperature of a modern elephant.

This method of “dental thermometry” provides a direct look into dinosaur physiology, moving beyond the indirect evidence paleontologists have relied upon for years. Previously, debates over whether dinosaurs were endotherms—animals that generate their own body heat like birds and mammals—hinged on bone microstructure, growth rates, and fossil locations. Some studies supported the endotherm hypothesis for various dinosaur lineages, while others suggested that thermal strategies may have varied across different species.