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T. Rex Had a Body Temperature of 97°F

59 pointsby marojejianyesterday at 5:13 PM102 commentsview on HN

gift link: https://www.nytimes.com/2026/09/16/science/trex-dinosaur-tem...

paper: https://www.science.org/doi/10.1126/sciadv.aeb7653


Comments

code_biologistyesterday at 6:56 PM

Repost from a different thread: Related only topically, a 1hr YouTube talk I enjoyed a lot: "Hatchling T. rex and the Evolution of Vertebrate Parental Care" by Nick Longrich: https://www.youtube.com/watch?v=zd0dR2n9hLA

He's a paleontologist and the talk starts with some pretty interesting statistical analysis aiming to estimate T rex clutch sizes (66 eggs) and hatchling weights (1.5kg) as well as T rex parental care. It ends with looking at evolutionary history trends in increasing parental investment in radically different animals.

He talks a little slow, so a little playback speed bump won't go amiss.

b0rtb0rttoday at 3:34 AM

the best part of this kind of science is that there’s no way to reproduce it or prove if it’s actually true, but it makes a great pop science article

laweijfmvoyesterday at 6:42 PM

How do we know its body temperature was 97 degrees, and simply not the environment was 97 degrees?

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strongwaddleyesterday at 6:50 PM

'Hotter than a crocodile, cooler than a chickennnnn....'

is the opening line to a great song i'll never get to hear.

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ChrisMarshallNYyesterday at 6:38 PM

Wouldn't be surprised if the smaller raptors had even higher body temps.

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SP3269yesterday at 9:36 PM

I’m missing Marc Bolan.

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ohyoutravelyesterday at 6:41 PM

This is really interesting, worth a read. Wouldn’t be surprised if the even larger dinosaurs had even higher body temps!

micromacrofootyesterday at 6:35 PM

> Up until the early 2000s, dinosaurs were thought to be rather reptilian and therefore probably coldblooded, Dr. Wiemann said. That began to change as multiple lines of evidence from geochemistry studies and CT scans of fossils showed they were warm-blooded. Dr. Wiemann had previously found that T. rex had a fast metabolism, but she said the new study did an “exquisite” job of zeroing in on a precise body temperature.

> To take the body temperature of a long extinct, school-bus-size predator, scientists at the University of California, Los Angeles, used a clever geochemistry technique on fossilized teeth, including two from “Thomas,” a famous T. rex in the collection of the National History Museum of Los Angeles County.

fascinating

we've also learned more about the air at the time via teeth, https://nautil.us/the-data-in-a-dinos-smile-1229729

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modzuyesterday at 6:50 PM

id assumed as much since seeing jurassic park in 1996

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lioetersyesterday at 6:36 PM

From the paper, that is: 36.3 ± 2.5°C.

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vereloyesterday at 9:06 PM

Please add the measurement system to the title. The times should know better...

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mepianyesterday at 6:33 PM

I read the headline in Celsius and thought that they were a bit too hot.

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john_strinlaiyesterday at 6:40 PM

i know its the nytimes, so we can assume american units, but i find it sort of crazy that even throughout the body of the article it doesnt ever say "fahrenheit".

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isomorphicyesterday at 6:53 PM

https://archive.is/20260916181240/https://www.nytimes.com/20...

(Even the NY Times gift link requires a login.)

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juancnyesterday at 7:47 PM

Wow! Close to boiling! /s

globular-toastyesterday at 6:42 PM

Farenheit. So a little bit cooler than us.

moomoo11yesterday at 6:44 PM

i will now believe this information until it becomes outdated in the future, at which point i will believe that information until it becomes outdated later

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ButlerianJihadyesterday at 9:18 PM

I can testify that my baseline body temperature (measured sublingually) is 97.6℉

By the way, Google Fit's body-temperature entry is cool, but when it comes to "Location", why is "mouth" in the middle of the list and next to some other, unrelated parts? How is the list being sorted?