T. Rex Had a Body Temperature of 97 Degrees

mmarojejian about 3 hours ago 48 commentsRead Article on nytimes.com

HI version is available. Content is displayed in original English for accuracy.

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

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

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Discussion (48 Comments)Read Original on HackerNews

lioeters•about 2 hours ago

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

Galilyou•about 2 hours ago

Phew! Thank you! I feel for the ungodly fahrenheit again

nmoon•about 2 hours ago

Fahrenheit is the superior measure

rf15•about 2 hours ago

counterpoint: it doesn't matter, since you need to learn relevant boiling/freezing temperatures on both scales anyway.

As a european: F is the only american system that is easy to use and reason with (considering its 0-100 range is spanning the "doable" temp range of too-cold to too-hot), unlike other imperial systems for lengths and whatnot.

WarmWash•about 2 hours ago

Better for day to day life, worse for science and engineering.

deagle50•about 1 hour ago

really is, and I grew up in celsius.

orbital-decay•about 2 hours ago

Thanks, I thought it was almost boiling.

gibspaulding•about 2 hours ago

So 97.3 ± 4.5 °F for anyone else curious how the precision translates.

mepian•about 2 hours ago

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

unsnap_biceps•about 1 hour ago

Would add a new fun dimension to Jurassic Park.

"Quick! Climb to 300 meters above sea level and the trex will boil and we will be safe!"

strongwaddle•about 2 hours ago

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

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

p1mrx•about 1 hour ago

With the power of AI slop, you can hear anything: https://pmarks.net/posted_links/trex_ai.mp3

dpe82•about 1 hour ago

The slop generator's gotchu: https://suno.com/s/gT2YhaQyNdlkzgeU

code_biologist•about 2 hours ago

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.

john_strinlai•about 2 hours ago

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".

BugsJustFindMe•about 2 hours ago

It doesn't need to. Any other unit would be either insanely cold or insanely hot.

skrebbel•about 2 hours ago

Given that it’s a shouty headline in a major publication, that’s what I would have expected.

bthrn•about 2 hours ago

Common sense suggests that living creatures are likely not boiling when they have a mild fever.

john_strinlai•about 2 hours ago

i am not a paleontologist and there have been many extremely weird living creatures over the time earth has been around.

and as the sibling comment mentions, i am primed for science articles to be metric.

falserum•about 2 hours ago

I’m metric all the way, but if it would use metric, it still should unambiguously state: C

vojtapol•about 2 hours ago

Common sense would be using metric units in science-related article.

SoftTalker•about 2 hours ago

It's a US-based newspaper written for the general public. Common sense would say it's using US units.

petcat•about 2 hours ago

Americans don't use Celsius when talking about their body temperatures, and that's who the audience is.

isomorphic•about 2 hours ago

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

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

laweijfmvo•about 2 hours ago

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

altcognito•about 2 hours ago

They compared against crocodilian teeth and those teeth were at a different temperature. Crocodilian teeth are known to be at a similar temperature to their environment because they are known to be cold blooded.

It is correct to say that we don't know they were warm blooded, just that their body temps were likely the given observed temperature.

cwmma•about 2 hours ago

If it was environmental then you'd expect it to fluctuate over time, but they also checked it against an animal they knew to be cold blooded, if it was environmental you'd expect them to be the same, but that animal was calculated by the same method to be colder.

pixl97•about 2 hours ago

What environment would stay at a constant 97 degrees?

surgi•about 2 hours ago

Europe this summer? /jk

ChrisMarshallNY•about 2 hours ago

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

layer8•about 2 hours ago

Seems sensible, given that birds have higher body temperatures.

hedgehog•about 1 hour ago

I didn't know this so I looked up the number for farm chickens, according to University of Kentucky (seems appropriate) they have a body temperature of "between 105°F and 107°F (40.6° and 41.7°C) ... Smaller chicken breeds have a higher body temperature than larger breeds"

https://afs.mgcafe.uky.edu/poultry/chapter-7-air-temperature

micromacrofoot•about 2 hours ago

> 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

SoftTalker•about 2 hours ago

It intuitively makes sense. A cold-blooded creature of that mass would take a long time to properly warm up or cool down. Most modern cold-blooded animals are small, e.g. frogs, snakes, lizards. They can move into the sunlight or shade as needed and pretty quickly change temperature.

globular-toast•about 2 hours ago

Farenheit. So a little bit cooler than us.

ohyoutravel•about 2 hours ago

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

modzu•about 2 hours ago

id assumed as much since seeing jurassic park in 1996

kilroy123•about 1 hour ago

It's actually older, from 1993.

moomoo11•about 2 hours ago

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

mindcandy•about 2 hours ago

Great! That's how knowledge is supposed to work.

partyficial•about 1 hour ago

that's not knowledge - that's just theory and belief.

you know, like religion.

juancn•42 minutes ago

Wow! Close to boiling! /s