However, a new article refutes this conclusion.
“These were very bold claims that required a second look,” says Cristian Gutierrez, a neuroscientist at the University of Alberta and co-author of a paper in “The Anatomical Record” that offers skepticism to with regard to the theory surrounding the intelligence of Tyrannosaurus Rex.
Suzana Herculano-Houzel of Vanderbilt University, Nashville, published research in 2023 that took data on the number of neurons in the brains of the evolutionary descendants of some dinosaurs, such as modern birds, reptiles and turtles , and applied them to fossilized brain cases of ancient lizards.
Writing in the “Journal of Comparative Neurology,” she concluded that Tyrannosaurus rex had between two and three billion neurons, the equivalent of those in the brains of intelligent primates, such as baboons.
“(This) would make these animals not only giants, but also long-lived animals with flexible cognition and therefore even more magnificent predators than previously thought,” she said. writing.
But no, replies Mr. Gutierrez.
He writes that Ms. Herculano significantly overestimated the size of the actual brain inside the skulls of tyrannosaurus rexes, which were much more closely related to modern crocodiles than to birds. Crocodile brain cases contain a significant amount of non-brain fluid and tissue, of which only 30% is devoted to gray matter.
Additionally, bird brains are much denser with neurons than reptile brains, further contradicting Herculano’s comparison.
Then there is body size. Even though the brain of a tyrannosaurus rex contained as many neurons as that of a baboon or a magpie, that brain had many more bodies to exploit.
“It is clear that larger animals need more neurons,” says Gutierrez.
“A T. rex had, say, two billion neurons, about the same as a baboon. But the t. rex weighed seven tons and the baboon weighs 40 kilos. It’s not the same, right?,” he explains.
Additionally, more neurons do not necessarily mean more intelligence, Gutierrez points out.
Giraffes have about two billion neurons, but are not known to use tools or transmit culture. Magpies, on the other hand, only have about 400 million neurons, but play games and hold “funerals” for their dead.
Ms. Herculano did not immediately respond to a request for comment on Mr. Gutierrez’s article, available since April 3.
Gutierrez says his previous research showed that there are correlations between behavior, brain size and the size of different parts of the brain.
“They’re not always simple correlations, but there are correlations. “It’s not completely crazy to look at the shape of the T. rex brain,” he says.
Dinosaurs more closely related to birds, such as Jurassic-era Archaeopteryx, had larger brains and could exhibit more complex, bird-like behavior, Gutierrez says.
Fossils provide some clues about how dinosaurs lived. They can, for example, show dinosaurs that cared for their young and lived in groups.
“But it will always be limited,” argued Mr. Gutierrez. That’s the only thing that’s not going to fossilize: behavior.”
An intelligent tyrannosaurus rex is highly unlikely, Gutierrez maintains. These monsters probably had an intelligence closer to that of a crocodile than that of a primate, so rest easy.
If the idea of a seven-ton crocodile lets you sleep easy.
