With its ruthless ability to hunt prey, there’s no denying that Tyrannosaurus rex was a clever beast.
But the famous dinosaur, which went extinct 66 million years ago, could not match today’s primates in intelligence, a new study shows.
Researchers last year poured cold water on a neuroscientist’s claim that T.Rex possessed “baboon-like” cognitive abilities and was capable of problem solving.
The controversial claim, which was immediately greeted with skepticism in the scientific community, has now been debunked.
Instead, T.Rex’s brain power was more similar to that of modern-day reptiles, such as crocodiles and lizards, the researchers claim.
It’s one of the most famous animals to grace 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, photo) was bipedal, meaning it walked on two legs
The new study was carried out by an international team of palaeontologists, behavioral scientists and neurologists, including experts from the University of Bristol and the University of Southampton.
‘The possibility that T. rex could have been as intelligent as a baboon is fascinating and terrifying, with the potential to reinvent our view of the past,’ says paleontologist Dr Darren Naish from the University of Southampton.
“But our research shows that all the data we have runs counter to this idea.
“They looked more like smart giant crocodiles, and that’s just as fascinating.”
Last year’s study, authored by Brazilian neuroscientist Dr. Suzana Herculano-Houzel, analyzed 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 its brain: 3.2 billion, even more than the 2.8 billion found in baboons.
Neurons, also known as nerve cells, are electrically excitable cells that transmit signals throughout an animal’s body.
Everything from eating, walking and thinking is made possible by neurons that send electrical and chemical signals between different parts of the brain and body.
The number of neurons usually correlates 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 skeleton cast in the Senckenberg Museum Frankfurt, Germany. T. rex lived at the end of the Cretaceous period (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 exhibit cultural behaviors .
In an excited tweet, she posted: “T. rex had baboon-like numbers of brain neurons, meaning he had what it takes to build tools, solve problems and live to be 40 years old, enough to build a culture!
‘Reality was actually scarier than the movies!’
For this new study, the researchers took a closer look at the techniques they used to predict both brain size and the number of neurons in dinosaur brains.
They found that previous assumptions about dinosaur brain size – and the number of neurons their brains contained – were unreliable.
Instead of 3 billion neurons, they say the number was at most 1.7 billion, but probably much less than this.
Relationship between brain and body mass in terrestrial vertebrates. Dinosaurs like T. rex have a brain-to-body ratio similar to that of living reptiles, team says
‘Our own calculations suggest that the T. rex forebrain contains up to 1.7 billion neurons,’ study author Dr Kai Caspar from Heinrich Heine University in Germany told MailOnline.
‘But we think figures of 250 to 350 million neurons are more likely.’
Dr. Caspar said there are “a host of issues” with the 2023 study.
‘Importantly, it assumes that the brains of dinosaurs such as T. Rex filled the entire cavity of the braincase,’ he told MailOnline.
‘While this is true for birds and us mammals, it is not true for reptiles, whose brains fill only about 30 to 50 percent of the cranial cavity.
‘The 2023 paper also extracted estimates of dinosaur brains and body mass from different and partly incompatible sources, resulting in a highly inconsistent data set.’
The researchers also challenge the idea that the more neurons an animal has in its brain, the more intelligent it is.
‘Although it may sound intuitive, results from behavioral studies show that neuron counts are often poor indicators of a species’ performance,’ Dr Caspar told MailOnline.
Footage compares the body and brain size of extinct animals, including Tyrannosaurus, and modern species
Here Tyrannosaurus imperator attacks a herd of the modern-day herbivorous 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 discriminative quantities – although pigeon brains have only a fraction of the number of neurons of monkey brains.’
Scientists are still struggling to understand what gives rise to behavior that “we might want to call intelligent,” the expert added.
But Dr. Caspar claims that reptiles are “certainly not as stupid as is commonly believed.”
“The behavior of these animals can be very complex and the experimental data we have points to many cognitive similarities between them, mammals and birds,” he said.
“So while there is no reason to believe that T. rex had ape-like habits, it was certainly a behaviorally sophisticated animal.”
T.Rex was able to ‘solve the problems that were relevant to him’ – such as subduing defensive prey, successfully courting mates and finding suitable nesting sites.
“What Herculano-Houzel was insinuating was that it used tools to achieve these things and passed on the acquired knowledge from one generation to the next,” Dr Caspar added.
“We simply have no evidence for this.”
MailOnline has contacted Dr Herculano-Houzel for comment on the new study, published today in The anatomical record.