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A New T. Rex Discovery

Scientists have discovered that Tyrannosaurus rex’s body temperature was similar to ours.

A T. rex walks on a well worn dirt path with trees and other vegetation, and two other dinosaur species, in the background.

© Orlando Florin Rosu/Dreamstime.com

T. rex was warmer than you might expect!

Scientists recently learned something new about the most notorious dinosaur ever. Tyrannosaurus rex’s body temperature was similar to the body temperature of a human.

Most scientists had already agreed that T. rex was warm-blooded, which means it could keep its body temperature stable. That is different from cold-blooded animals, like alligators and snakes, whose body temperatures change to match their environments.

T. rex would have been able to live in both hot and cold areas because its body temperature would not have been affected by the outside air. This ability to survive just about anywhere may have helped T. rex become a top predator.

Scientists learned about T. rex’s body temperature by studying fossilized T. rex teeth. Atoms inside tooth enamel are arranged in different ways depending on an animal’s body temperature.

In the case of T. rex, that temperature was about 97 degrees Fahrenheit (36 degrees Celsius). That’s about the same as an elephant’s temperature and not very different from the usual human body temperature of about 98.6 degrees F (37 degrees C). 

This is the first time scientists have been able to determine just how warm T. rex’s body was. 

“We figured out how warm the most famous animal of all, a T. rex, was,” Aradhna Tripati, a geochemist who worked on the study, told the Associated Press.

Scientists look forward to using the tooth enamel method to determine the body temperatures of other extinct species. This information could help scientists understand how these species survived in their environments.

NEWS EXTRA

Backpack Wins Fat Bear Week

The brown bear called Backpack stands in rapidly moving water facing to the left of the camera.

Courtesy explore.org

As a cub, Backpack used to ride on his mother’s back when they swam. That’s where he got his name.

All the bears of Alaska’s Katmai National Park are fattening up for the winter, but there can be only one winner of the annual Fat Bear contest. This year’s top prize goes to a 1,200-pound (540-kilogram) gentle giant named Backpack.

Fat Bear Week takes place each fall as Alaskan brown bears fatten up on salmon to prepare for the long winter ahead. The public votes online to choose the bear that has bulked up the best. Backpack received more than 100,000 online votes to win a close victory against Bear 910, also known as “Dancing Queen.”

Backpack is a quiet bear, known for sitting on a riverside rock for long periods of time. Maybe he’s confident in his dominance over other bears. After all, his mother, Holly, is a former Fat Bear Week champion.

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Did You Know?

A world map shows dots at all the major dinosaur fossil sites, and they are located on all the continents.

Encyclopædia Britannica, Inc.

If you could go back in time to the dinosaur age, you’d find T. rex in western North America. Would you look for one?

How Fast Was T. Rex?

A dinosaur wears a tracksuit and sneakers and runs on a track.

© STOCK_wiN, Alina Mosinyan, Graphicook Studio/stock.adobe.com; Photo illustration Encyclopædia Britannica, Inc.

T. rex weighed about as much as an elephant. But was it as slow as an elephant? 

Some scientists believe that T. rex was slow. Like today’s big land animals, it may have been too big and heavy to run very fast. According to these scientists, T. rex’s top running speed would have been about 10 miles per hour (16 kilometers per hour), or about as fast as a human.

Others think T. rex was surprisingly swift. A 2026 study found that these dinosaurs walked on their tiptoes, like modern birds. This may have allowed them to run at speeds of up to 25 miles per hour (40 kilometers per hour)!

Sink Your Teeth Into This!

The full skeleton of a T. rex called Sue is on display in a museum.

© Koichi Kamoshida/Getty Images

How many teeth did T. rex have, and what did this massive dinosaur eat? 

Learn more about T. rex at Britannica!

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tyrannical

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adjective

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: using power over people in a way that is cruel and unfair

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How to Cite This Page

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“In the News: A New T. Rex Discovery.” Britannica School, Encyclopaedia Britannica, 4 Oct. 2026. https://news.eb.com/level1/a-new-t-rex-discovery. Accessed 5 Oct. 2026 [Replace this date with today’s date.]