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Since the seventies , most scientist have agreed thatTyrannosaurus rexwas about as smart as modern reptiles .
Then , in 2023,a studyby a Brazilian neuroscientist argued thatT. rexhad a cognitive intelligence nigher to that of primates . Could this iconicdinosaurhave been as smart as a baboon , or even a man ?
Just how smart was T. rex?
plausibly not , finds a new subject field published in the journalThe Anatomical Record . The international team of scientists reaffirm the older understanding thatT. rexintelligence was likely similar to that of a crocodile .
" This traditional opinion is potential the right one , " first authorKai Caspar , a zoologist at Heinrich Heine University Düsseldorf in Germany , told Live Science . Caspar studies how cognition evolves and the different cognitive capacities between animal groups .
To study brain biota in long - extinct animals like dinosaurs , scientists apply endocasts — or mould of the fogy skull — to count on relative brain size and the symmetry of tissue paper that it once held . It ’s not a perfect proxy , but presently it ’s the best model .
In modern alligator and crocodile , the brain only occupy about 30 % of the cranial cavity . In bird and mammal , it ’s close to 100 % .
touch : Never listen outrunning a T. rex — you could probably outwalk it
concord to Caspar and his colleagues , this was one of the main problem with the 2023 study : that it overestimated the brain sizing ofT. rexby adopt the brain filled the whole endocranial caries . hold the shape and build of the dinosaur endocasts available to analyze , Caspar say the brainiac - to - fluid ratio was likely closer to that of reptilian than that of innovative razz .
The 2nd problem was data mutual exclusiveness . Brain size idea in the Brazilian subject field include other social structure in theT. rexhead that sit inside the brain cavity but are n’t part of the brain itself , such as the olfactory medulla oblongata . The data also used a mix of juvenile and adultT. rexsamples .
In the young cogitation , Caspar and colleagues tidied up the dataset by standardizing body hoi polloi estimate and excluding those structures insideT. rex ’s skull that are n’t take in neuronic natural action , like the olfactory bulb , pituitary secretory organ and inner pinna .
But they could n’t replicate the results of the 2023 study .
" We arrived at very different results , " read Caspar .
They estimated the number of neurons , or nerve jail cell , in theT. rexbrain using their new encephalon volume reckon .
They foundT. rexhad between 250 million and 1.7 billion neuron , similar to the count in crocodile . The Brazilian study , in contrast , estimated 3.3 billion neurons forT. rex , like to that of baboon .
However , the field mark that brain size and neuron count are n’t the best prognosticator of cognitive intelligence . The number of neurons and brain sizing varies greatly across creature , but it does n’t always correlate to higher competence .
For model , pigeonshave fiddling genius and high nerve cell density and can count as well as monkeys with a larger brain .
" Neuron counts have not proven themselves to be very skilful predictors of intelligence in modern animals . So why should we assume that they are for extinct one ? " Caspar said .
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Even thoughT. rexprobably had the intelligence of a crocodile , Caspar said not to consider it a downgrade from primate - level tidings .
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A whole range of dinosaur behavior have been lose to time and sympathize more about T. king brain biology can help inform the field of modern reptile , allege Caspar .
" To say that dinosaur resemble living reptile in their noesis does n’t think that they were boring animals , " he said . " reptile can be fascinating as well . "
