With its ruthless ability to hunt down prey, there’s no denying that Tyrannosaurus rex was a clever beast.
But the famous dinosaur, which died out 66 million years ago, couldn’t match today’s primates for intelligence, a new study shows.
Researchers have poured cold water on the claim by a neuroscientist last year that T.Rex possessed ‘baboon-like’ cognitive abilities and was capable of problem-solving.
The controversial claim, immediately greeted with skepticism in the scientific community, has now been debunked.
Instead, T.Rex’s brain power was more like that of today’s reptiles, such as crocodiles and lizards, the researchers argue.
It is one of the most famous animals to have graced our planet, but the T.Rex didn’t quite have the intelligence of today’s primates, a new study says. Like other dinosaurs, Tyrannosaurus rex (T.Rex, pictured) was bipedal – meaning it walked on two legs
The new study was conducted by an international team of palaeontologists, behavioural scientists and neurologists, including experts at the University of Bristol and University of Southampton.
‘The possibility that T. rex might have been as intelligent as a baboon is fascinating and terrifying, with the potential to reinvent our view of the past,’ said University of Southampton palaeontologist Dr Darren Naish.
‘But our study shows how all the data we have is against this idea.
‘They were more like smart giant crocodiles, and that’s just as fascinating.’
Last year’s study, authored by Brazilian neuroscientist Dr Suzana Herculano-Houzel, analysed T.Rex skulls and studied the brains of dinosaur descendants, including modern birds.
She estimated that T. rex had an exceptionally high number of neurons in the brain – 3.2 billion, even more than the 2.8 billion found in baboons.
Also known as nerve cells, neurons are electrically excitable cells that transmit signals throughout an animal’s body.
Everything from eating, walking and thinking are facilitated by neurons sending electrical and chemical signals between different areas of the brain and the body.
Neuron counts usually correlate with brain size, so a T. Rex skeleton with a large brain cavity would have had a larger brain and therefore more neurons.
Image of a T. rex skeletal cast at Senckenberg Museum Frankfurt, Germany. T. rex lived at the end of the Cretaceous (about 66 million years ago) and was exclusive to western North America
Studies also suggest that the more neurons an animal has, the more intelligent it is, leading the neuroscientist to suggest that T. Rex would have been able to solve problems, create tools to use and even engage in cultural behaviours.
In an excited tweet, she posted: ‘T. rex had baboon-like numbers of brain neurons, which means it had what it takes to build tools, solve problems, and live up to 40 years, enough to build a culture!
‘Reality was actually MORE terrifying than the movies!’
For this new study, the researchers took a closer look at the techniques she used to predict both brain size and neuron numbers in dinosaur brains.
They found that previous assumptions about brain size in dinosaurs – and the number of neurons their brains contained – were unreliable.
Rather than 3 billion neurons, they say the number was 1.7 billion at the very most, but likely a lot less than this.
Relationship between brain and body mass in land-living vertebrates. Dinosaurs like T. rex have brain to body size ratios similar to those of living reptiles, the team say
READ MORE: How T.Rex delivered its bone crushing bites
Researchers used CT scans of dinosaur fossils and modern-day specimens to create a 3D computer model of a dinosaur jaw
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‘Our own calculations suggest that the T. rex forebrain contained 1.7 billion neurons at a maximum,’ study author Dr Kai Caspar at Heinrich Heine University in Germany told MailOnline.
‘But we consider figures of 250 to 350 million neurons more likely.’
Dr Caspar said there’s a ‘great number of issues’ with the 2023 study.
‘Importantly, it assumes that the brains of dinosaurs such as T. Rex filled the complete cavity of the braincase,’ he told MailOnline.
‘While this is true for birds and us mammals, it is not for reptiles, the brain of which fills only about 30 to 50 per cent of the skull cavity.
‘The 2023 paper also took its dinosaur brain and body mass estimates from various and in parts non-compatible sources, which resulted in a highly inconsistent dataset.’
The researchers also contest the idea that that the more neurons an animal has in the brain the more intelligent it is.
‘Although it might sound intuitive, results from behavioral studies show that neuron numbers are often bad indicators of the performance of a species,’ Dr Caspar told MailOnline.
Imagery compares the body and brain size of extinct animals, including the Tyrannosaur, and modern-day species
Here, Tyrannosaurus imperator attacks a herd of the contemporary plant-eating dinosaur Triceratops horridus
‘For example, pigeons have been shown to perform at the same level as monkeys when it comes to short-term memory or discriminating quantities – although pigeon brains only have a fraction of the neuron counts of monkey brains.’
Scientists are still struggling to make sense of what gives rise to behaviour that ‘we might want to call intelligent’, the expert added.
But Dr Caspar claims reptiles are ‘certainly not as dim-witted as is commonly believed’.
‘They’re behaviors can be very complex and the experimental data we have point to many cognitive similarities between them, mammals and birds,’ he said.
‘So whereas there is no reason to assume that T. rex had monkey-like habits, it was certainly a behaviorally sophisticated animal.’
T.Rex was able to ‘solve the problems that were relevant to it’ – such as subduing defensive prey, successfully courting mates and finding suitable places to nest.
‘What Herculano-Houzel was insinuating was that it used tools to achieve these things and passed down acquired knowledge from one generation to the other,’ Dr Caspar added.
‘For this, we simply have no evidence.’
MailOnline has contacted Dr Herculano-Houzel for comment about the new study, which is published today in The Anatomical Record.
