Scientists Discover T. Rex Blood Was As Hot As Human Blood, Suggesting They Were Fast-Running Predators

Using a novel technique, a team of scientists at UCLA have managed to take the body temperature of a Tyrannosaurus rex. Despite being extinct for over 65 million years, the T. rex could be studied because the team discovered a power beyond time, beyond death: dentistry. Examining the isotopes in the molecules of the enamel, the researchers have now announced that the world's most famous dinosaur had an internal temperature of 97 degrees Fahrenheit, give or take a few degrees. That's roughly the same as you or I, or your best elephant friend. This is proof that T. rex was indeed warm-blooded, as long suspected, as opposed to most other reptiles. That in turn suggests that T. rex was an active and fast-running predator or scavenger, rather than a sit-and-wait ambush predator like a crocodile. Speed definitely makes them worthy of our little blog.

The breakthrough comes courtesy of a technique developed at UCLA about ten years ago, which looks at the molecules preserved in fossils. Carbon and oxygen are very common ingredients, but they do come in different flavors, or "isotopes," based on how many neutrons they have. It turns out that the heavier isotopes bond with each other into molecules at different rates than their lighter cousins, based on temperature. So running an analysis of the isotopes within a fossil can reverse-engineer what the body temperature must have been. Since enamel changes the least over time, its best to do this technique with a tooth sample.

Still, there's an issue: There are only so many dinosaur teeth that have been found, so shaving some of them off for analysis risks degrading the few that we have. For the last decade, the technique simply required too much mass from a tooth for anyone to allow the UCLA team to touch their fossils. What changed was the technique itself, which became more refined. Now able to get good results with very little mass, the team convinced the nearby Natural History Museum in Los Angeles to let them scrape off a few precious samples. Thomas the T. rex and one of his buddies became the first dinosaurs ever to have their temperature taken.