T. Rex Body Temperature Found to Match Human Norms

The study, published in Science Advances, analyzed samples from the teeth of 'Thomas,' a 70% complete skeleton unearthed in Montana in 2003. By examining the carbon and oxygen isotopes within the enamel, geoscientists determined that the mineral bonds formed at a temperature remarkably close to that of modern humans. Refining this technique over a decade allowed the team to extract data while reducing the required fossil material by 90%.

This evidence of endothermy suggests the T. rex was a high-energy organism, capable of sustained activity and migration in cooler climates. Co-author Robert Eagle noted that a warm-bodied physiology dictates significant behavioral constraints, including higher caloric intake requirements to fuel an active metabolism. Rather than a sluggish animal dependent on external heat, the T. rex likely functioned as a dynamic hunter or scavenger. This isotopic thermometer method, now applied to species ranging from woolly mammoths to megalodons, offers a new lens for understanding the metabolic lives of creatures that roamed the Earth during the Late Cretaceous period.