T. rex-like dinosaurs were the primates of their time

Suzana Herculano-Houzel just discovered that Tyrannosaurus rex didn't just have the big body and huge claws and gigantic teeth: it probably also had as many neurons in the telencephalon as... a modern baboon. Now THAT is truly terrifying. How could she possibly say that, and why should you care? Watch and see!
Original paper is here: onlinelibrary.wiley.com/doi/f...
Take Suzana Herculano-Houzel's Crash Course in Neuroscience!
In English: www.suzanaherculanohouzel.com...
In Portuguese: www.suzanaherculanohouzel.com...
To stay up to date with Suzana and all of her latest discoveries:
TWITTER: @suzanahh
INSTAGRAM: @suzanaherculanohouzzelforreal
TIKTOK: @suzana.herculano
To check out all of Suzana's on-line educational courses and all of her latest scientific papers go to her website:
suzanaherculanohouzel.com

[@D3is3l]

Suzana, you're a beast, you need more subscribers with such awesome production like this!

[@suzanaherculano]

Thanks! Help me spread the word, please!

[@sombertempest4840]

Your research has flipped the paleontology world on its head. You explain complex science in a way that’s easy to understand as well. Outstanding.

[@khaleelrashad2146]

This is such an interesting topic. I never expected a t-Rex to be as intelligent as any modern primates. Now I have a newfound respect for dinosaurs.

[@creaturecore13]

They weren't, paleontologist have said how incorrect this is.

[@vanessapenna4481]

It's so cool! Heading now to download this paper. I'm so excited about the idea of you coming to Australia and teaching us both your neuron soup :)

[@julianmerget203]

wow, awesome video. Our prof. put it in his lecture and it was just a treat. Warm greetings from Germany :D

[@symmetry08]

I think T-rex lived about until 70 years or so, as it was large being and needed to grow up to size and had few species that could challenged them. Also, lived in relative warmth due to its sheer size, so bones had less trouble to degenarations with age. However, 70 years of age is relative perspective if that one can survive all obstucles that comes life in nature.

[@homebrewznz3482]

Its not surprising that they would be quite smart. They had a long time to evolve

[@Asdfqwerty1243]

I'm not sure how you can assume that the quadrapedal dinos were more cold blooded when we have pro-sauropods that eventually became bipedal. Also most herbivores usually have smaller brains and that's the same in mammals too with some exceptions like really large mammals like elephants and whales. Does your technique take into consideration the actual size the brain of T-rex to match this level of intelligence? Also what about the necessary cooling features? Do the fossils that we have indicate any form of advanced cooling for such an active brain?

[@richardblazer8070]

The literal size of an animal’s brain isn’t really indicative of an animal’s intelligence, nor is the brain to body ratio. Elephant brains are much larger than ours, but we are smarter than them, and elephants and many birds are far smarter than their brain to body ratio would suggest. And we know tyrannosaurids actually had crocodilian-like cooling systems around the eyes and brain.

[@justinianthegreat1444]

If T Rex is as smart as a primate then that would make the T Rex even more scarier

[@annemarielara1962]

Very interesting theory. Definitely food for thought!

[@eksffa]

Dear prof SHH, I quite did not get the method. If dinosaurs with high density of neurons in the cerebral cortex were to apply this method and math to find out how is the brain of humans, and they assumed correctly humans were primates and they knew other primates for a reference, they would calculate the density and size of human brains correctly but wouldn’t they just call humans ordinary average apes? Maybe chimps, but… what makes humans different by the same method would they find out? I reliable can we assume this method is valid if that special quality not dinos existed and how reliable could they assume humans are or are not special quality of apes with this topology of brains with dense cortex and a self reference network which could allow this kind of monkey to understand the incompleteness of mathematics and create Turing machines?

[@suzanaherculano]

Hi there, we applied this method to human brains, and the results published in 2009 showed that the human brain IS this generic primate brain that you posit! That doesn’t disqualify humans; we still have THE MOST neurons in the cerebral cortex, which seems to be the best explanation for our cognitive prowess. Check out my website, www.suzanaherculanohouzel.com

[@eksffa]

@@suzanaherculano Hello prof, thank hoje got your time replying me. Yes I got it but I got quantitatively, would this method suggest we are humans, in this sense of what makes us humans, the high density of neurons and specific functions of neurons as you explain in your crash course, or would we just figure out numbers but not the distribution, functions and topology of brains? From brain to soup to numbers OK But from the numbers to HUMAN brains and nit other sort of primates, could this method predict? Aka predict the mass of the cortex, aka predict there THE MOST (as you put it) of the neurons are at, in humans or in dinos from the closest relative bird.

[@fe80.1.1]

@@eksffaI think the answer to what you are asking is no. Reading the paper we can see the expected number of neurons in certain regions were taken from relative reference of what is known, such as Kerkova et al (2022) therefore the method scales and projects the numbers, quantitatively as you put it. If an evolution leap would lead to different arrangements of neuron distribution such as what makes humans a remarkable species of primates, I don’t think the method could tell. From apes to apes it would but from apes to Neanderthal, from there to Homo Erectus and later to humans, possibility only quantities and not arrangements. This is how I understood the paper. A quantitative projection of neurons keeping the same arrangement relative to the reference birds.

[@eksffa]

@@fe80.1.1 but apes DO have prefrontal cortex, right? wouldn’t the method (I could not tell from the paper) predict the quantitative density growth through evolutive time?

[@italucenaz]

@@eksffa I guess so, but then, apparently early Homo sapiens and Neanderthals for a brief momment in the past had significantly bigger brains than nowadays people, this mean they used their brain for more things in the past, not that they would be better at math or linguistics, it's complicated

[@stefanostokatlidis4861]

Did they need this much cognitive specialization though? In modern terrestrial ecosystems, the most intelligent animals tend to be medium-sized omnivores or carnivores with varied and changing sources of food, like primates, procyonids and corvids. Top predators are already specialized in what they do and physically they are already unchallenged by any other animal smaller than them. Also, such a large carnivore like T-Rex would probably need a lot of food and would view other conspecifics as competition. There is no evidence of social living in tyrannosaurids. Also not all lizards are dumb and monitor lizards for example are quite flexible learners and almost mammalian in their ecology. A t-Rex with monitor intelligence would still be crafty and terrifying. The problem is that ectothermic reptiles are Chroniclely underfunded and reptile research doesn’t communicate regularly with ornithology or palaeontology. I believe that smaller and omnivorous dinosaurs could be even more intelligent.

[@shiftysdad]

Very interesting! Have you done a similar assessment for dromeosaurids (e.g. velociraptor) and troodontids? Troodontids had some of the highest EQs of all the dinosaurs, so I'd be curious to see if they were still considered some of the most intelligent dinosaurs based on this new assessment.

[@suzanaherculano]

Yes, it’s in the paper. The number of neurons is proportional to the size of the brain, so since it was not particularly large…

[@lucasvillar2236]

Você orgulha o Brasil! Grande cientista!

[@tueferbenz7492]

Very interesting! I'm guessing that big Cenozoic birds like Gastornis & Phorusrhacos were pretty smart?

[@dinobotcypertron4602]

Grimlock's New Brain | Transformers: Generation 1 | Season 3 | E24 😆

[@LMJr88]

Why does this make me pause in confusion every time I think about it. Dinosaurs could use tools like primates and have social hierarchies?

[@dinokmegminden]

tiny detail: Chicxulub asteroid hit the planet 66.038 MYA

[@suzanaherculano]

Correct, thanks!

[@tyrannotherium7873]

Tyrannosaurus rex was a smart animal, but it was probably smart as a Crocodile not as a primate

[@ElisaAssis-tc3sx]

Surpreemdete

[@matthewmarx3546]

I think your work is very sound, Suzana! I actually was a little less surprised to hear that non avian theropods had neuronal structures similar to today's birds. However, there are some problems with your theory. Firstly, the oldest Tyrannosaurus specimen we currently have (SUE) was twenty-eight years old when it died, and before that it was suffering from arthritis which is something that you would expect from an aging animal. Secondly, while I like the idea of carnosaurs and tyrannosaurs having birdlike neuronal structures, these creatures actually had brains that were shaped like that of a crocodile which is sausage shaped. And finally, some people claim that the techniques you used to measure brain-to-body size were rather outdated by today's standards.

[@suzanaherculano]

Hi Matthew, thanks. The 40 years estimate is for MAXIMAL longevity, and wild animals typically die well before that, so the problem would be if fossils were aged 60 years, not 30. Also, the shape of the brain is highly variable and doesn’t mean anything - see dogs. Last: the fact that there are some more modern estimates now doesn’t mean that the previous ones were off by 5x. Half the number of neurons would STILL make Trex have monkey-like numbers of neurons…

[@matthewmarx3546]

@@suzanaherculano All right, I see your point. Thank you for telling all of this. But what about forcing a mammalian life history based on a number of telencephalic neurons? The fossil record does not show that. Also, in the first decade of their life, tyrannosaurs lived as long-legged juveniles filling in the mid-sized predator niche while their bigger bulkier parents were giant ambush predators. Even the youngest Tyrannosaurus specimen we currently have (Jane) was eleven to thirteen years old when it died so it must have been sexually mature at that age despite not being fully grown. Then again, the debate on dinosaur growth curves is still ongoing.

[@suzanaherculano]

It’s not “forcing” a “mammalian” life history. Numbers of telencephalic neurons predict 74% of variation in maximal longevity across ALL warm-blooded vertebrates: mammals (humans included) AND birds. That’s the first time that birds are finally NOT outliers in their longevity, like they seem to be if you use body size as a predictor - which is a poor (about 30% of variation) predictor AND not universal! Check out my 2019 paper on longevity: www.suzanaherculanohouzel.com/uploads/1/1/5/3/115389475/herculanohouzel-2019-pbr.pdf

[@matthewmarx3546]

@@suzanaherculano Very good work! Do you plan on doing more assessments on more prehistoric animals such as gorgonopsians and ornithinopod dinosaurs?

[@suzanaherculano]

Sure! Any species I can find good estimates of brain and body size…

[@supersaiyantayt]

Chrono trigger.....

[@elperrotrepapinos]

An avian tooling researcher here (Goffin's cockatoos). I've been following your work (through papers) for many years, and it's great to discover your new channel here. Congrats for such a fascinating paper.

[@toska3528]

I like how she refers to the t-rex as, "the royal tyrant lizard," when tyrannosaurus rex literally means, "tyrant lizard king," in Latin. I don't think that is merely a stylization choice, I think it's a thinly veiled feminist bias; "oh, we can't use masculine terms because that'd be patriarchal!" She's probably going to give me a dissertation about, "how tyrannosaurus rex perpetuates patriarchy," now.

[@TRS-Eric]

That movie exists, it's the Super Mario Bros movie!

[@nolanueno1060]

Random Human: Dinosaurs are stupid. Carnivore Dinosaurs: Want say that again? Random Human: mommy.... CRUSH