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Thursday, September 17, 2026

Scientists took a T. rex’s temperature: 97 degrees

Researchers read chemical patterns in the enamel of three fossil teeth to work out how warm Tyrannosaurus rex ran. The answer is about 97 degrees Fahrenheit, close to a human and about the same as an elephant. Most scientists agreed T. rex was warm-blooded but never had a number. The study came out Wednesday in Science Advances.

PBS NewsHour, pbs.org/newshourPhoto: ScottRobertAnselmo, Wikimedia Commons, CC BY-SA 3.0
Ages 5–7
Good one to bring up

Scientists found out how warm a T. rex was, and it was about as warm as you. They did it with three of its teeth, which keep a record of body heat like a thermometer you can read a very long time later. Put your hand on your forehead: that’s about how warm a T. rex felt inside. The dinosaurs are long gone, so this one only bites in museums.

Why it worksDinosaurs and their own body are two things a six-year-old already cares about.

They might ask
“Was T. rex as warm as me?”
Almost. About 97 degrees, and you are usually 97 to 99. An elephant is about the same.

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Ages 8–12
Good one to bring up

Most scientists agree T. rex was warm-blooded, but nobody had a number. Atoms in tooth enamel clump into patterns that depend on body heat, so three fossil teeth worked like a thermometer. The reading: about 97 degrees, close to you.

Why it worksGuess, test, number is the science chain they learn at school.

They might ask
“How hot was a T. rex inside?”
About 97 degrees, like you. Scientists read it from atoms in three fossil teeth.
“Why does it matter how warm it was?”
A steady temperature let T. rex live across cooler and hotter parts of North America.

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Ages 13–17
Ask first, then talk

How do you take the temperature of an animal you only know from fossils? For T. rex, you read the atoms in its tooth enamel. Three teeth gave about 97 degrees, and one paleobiologist says she expected hotter, more like a bird. What else could this trick tell us?

Why it worksTeens like the method more than the fact. Let them poke at it.

They might ask
“So it was warm-blooded?”
Most scientists already thought so. This is the first firm number. One expert expected a few degrees hotter, like a bird.
“Can they do this for other dinosaurs?”
The team says that’s next. A co-author says lots of “charismatic species” could be tested the same way.

Also written for and .

The dinner table question

If you could ask a T. rex one question, what would it be?

Ask it at any age. Anyone can answer it, including the ones who didn’t read the news.

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