A 66-million-year-old tooth reveals T. rex was nearly as warm as a human

Chemical clues preserved inside fossilized T. Rex teeth reveal that the dinosaur maintained a body temperature of about 97 degrees Fahrenheit, almost identical to humans. The finding provides direct evidence that the giant predator was warm-blooded, helping explain how it stayed active and survived in chilly environments as far north as Alaska.

A 66-million-year-old tooth reveals T. rex was nearly as warm as a human. Rex was nearly as warm as a human Fossilized teeth reveal that T. Rex ran at about 97 degrees Fahrenheit, giving scientists their first direct evidence of just how warm-blooded the giant predator really was.

Fossils discovered as far north as Alaska have suggested that T. Rex could tolerate cold conditions, adding to evidence that the giant dinosaur was moving away from the cold-blooded physiology of many reptiles and toward the warm-blooded metabolism seen in birds. Now scientists have done something that once seemed impossible: they have effectively taken T.