Scientists have determined that the Tyrannosaurus rex maintained a body temperature close to that of modern humans, challenging previous assumptions about dinosaur physiology. By analyzing fossilized teeth, researchers estimated the dinosaur’s core temperature to be approximately 97 degrees Fahrenheit (36 degrees Celsius), a finding published on Wednesday in the journal *Science Advances*.
Traditionally, dinosaurs were thought to be cold-blooded and sluggish, but later research suggested that some species, particularly theropods like T. rex, were warm-blooded with the ability to regulate their internal temperatures. Still, establishing a precise temperature for an extinct animal has remained elusive.
The research team employed a novel chemical method focusing on the atomic structure within the enamel of three T. rex teeth. This structure changes in predictable ways depending on the body temperature of the animal at the time the enamel formed. “We figured out how warm the most famous animal of all, a T. rex, was,” said Aradhna Tripati, a geochemist at the University of California, Los Angeles, and coauthor of the study.
The results place T. rex’s body temperature near that of modern elephants and within range of human body temperature, which typically varies between 97 and 99 degrees Fahrenheit (36 to 37 degrees Celsius). Some experts, such as Jasmina Wiemann, a paleobiologist at Johns Hopkins University, expressed surprise at the relatively moderate reading. Based on earlier research on dinosaur metabolism, Wiemann hypothesized that T. rex might have had a higher temperature, possibly closer to that of modern birds, which are its evolutionary descendants.
Understanding T. rex’s body temperature could provide new insights into its ecological role and behavior. Maintaining a stable internal temperature in diverse climates would have allowed the predator to inhabit a wide range across prehistoric North America. The thermal regulation might also relate to its hunting strategies and energy requirements in sustaining its position as an apex predator.
The study's authors emphasize the importance of applying this enamel-based temperature measurement technique to other dinosaur species to better understand the spectrum of metabolic adaptations during the Mesozoic Era. “There’s lots of interesting, charismatic species that could be explored using this,” said Robert Eagle, a geobiologist at UCLA and coauthor of the study.
As research progresses, these findings could reshape longstanding views on dinosaur biology and ecology by offering a more precise look at the thermal physiology of these ancient animals.