The king of dinosaurs was not a genius! Scientists are pouring cold water on the theory that the T.Rex was as smart as an ape

• The study indicated that the fearsome dinosaur species had the intelligence of primates
• Experts say the results are unreliable, and that T. rex was as intelligent as today's reptiles

With its ruthless ability to stalk prey, there's no denying that T. rex was an intelligent beast.

A new study shows that the famous dinosaurs, which became extinct 66 million years ago, could not match modern primates in terms of intelligence.

Researchers poured cold water on a neuroscientist's claim last year that the T.Rex had “baboon-like” cognitive abilities and was able to solve problems.

This controversial claim, which was immediately met with skepticism in the scientific community, has now been debunked.

Instead, T. rex's brain power was more similar to that of modern reptiles, such as crocodiles and lizards, the researchers say.

The new study was conducted by an international team of paleontologists, ethologists and neurologists, including experts at the University of Bristol and the University of Southampton.

Dr Darren Naish, a paleontologist at the University of Southampton, said: “The possibility that T. rex could be as intelligent as a baboon is both fascinating and terrifying, with the potential to reinvent our view of the past.”

“But our study shows how all the data we have contradicts this idea.

“They were like giant, intelligent crocodiles, which is quite remarkable.”

Last year's study, by Brazilian neuroscientist Dr. Susana Herculano-Hozel, analyzed T. rex skulls and studied the brains of dinosaur descendants, including modern birds.

She estimated that T. rex had an exceptionally large number of neurons in its brain — 3.2 billion, even more than the 2.8 billion found in baboons.

Also known as nerve cells, nerve cells are electrically excitable cells that transmit signals throughout an animal's body.

Everything from eating, walking, and thinking are facilitated by neurons that send electrical and chemical signals between different areas of the brain and body.

The number of neurons is usually related to brain size, so a T. Rex skeleton with a large brain cavity would have a larger brain and thus a greater number of neurons.

Studies also suggest that the more neurons an animal has, the more intelligent it is, leading a neuroscientist to suggest that T. Rex was able to solve problems, create tools to use, and even engage in cultural behaviors.

In excited tweet, published: 'T. Rex had a baboon-like number of neurons in its brain, meaning it had what it took to build tools, solve problems, and live up to 40 years, enough to build a culture!

“The reality was actually scarier than the movies!”

In this new study, researchers took a closer look at the techniques used to predict brain size and neuron numbers in dinosaur brains.

They found that previous assumptions about brain size in dinosaurs – and how many neurons their brains contained – were not reliable.

Instead of 3 billion neurons, they say the number was at most 1.7 billion, but it is likely much lower than this.

“Our own calculations indicate that the forebrain of T. rex contains a maximum of 1.7 billion neurons,” study author Dr Kai Caspar from Heinrich-Heine University in Germany told MailOnline.

“But we consider numbers in the range of 250 to 350 million neurons to be more likely.”

Dr. Kaspar said there were “a large number of problems” with the 2023 study.

“More importantly, it assumes that the brains of dinosaurs such as T. Rex filled the entire cavity of the brain skull,” he told MailOnline.

While this applies to birds and mammals, it does not apply to reptiles, whose brains fill only about 30 to 50 percent of the cranial cavity.

“The 2023 paper also took estimates of dinosaur brain and body mass from different sources and are incompatible in parts, resulting in a highly inconsistent data set.”

Researchers also question the idea that the more neurons an animal has in its brain, the more intelligent it is.

Dr Kaspar told MailOnline: 'Although it may seem intuitive, results from behavioral studies show that neuron numbers are often poor indicators of species performance.'

“For example, pigeons have been shown to perform at the same level as monkeys when it comes to short-term memory or discriminative quantities – even though pigeon brains contain only a small fraction of the number of neurons in monkey brains.”

The expert added that scientists are still struggling to understand what leads to behavior that “we might want to describe as intelligence.”

But Dr. Kaspar claims that reptiles are “certainly not as stupid as commonly thought.”

“Their behaviors can be very complex and the experimental data we have indicates many cognitive similarities between them and mammals and birds,” he said.

“Thus, while there is no reason to assume that Tyrannosaurus had ape-like habits, it was certainly a behaviorally sophisticated animal.”

The T.Rex was able to “solve relevant problems” – such as subduing defensive prey, successfully courting mates, and finding suitable nest sites.

Dr Caspar added: “What Herculano-Houzel was alluding to is that she uses tools to achieve these things and the knowledge gained is passed on from one generation to the next.”

“For this, we simply have no evidence.”

MailOnline contacted Dr Herculano-Houzel for comment on the new study, published today in Anatomical record.