Last year, neurobiologist Susana Herculano-Ouzel made the controversial statement in her scientific study that carnivorous dinosaurs such as tyrannosaurs were comparable to primates in terms of intelligence. An international team of paleontologists, biologists, and experts in neuroanatomy and cognitive psychology has published a new study arguing for the opposite conclusion.
In an article published in 2023 Journal of Comparative NeurologyHerculano-Ouzel tried to calculate how many neurons there might be in the brain using the phylogenetic bracketing method. Tyrannosaurus rex and similar predatory dinosaurs. The scientist claimed that the number of neurons in them roughly corresponds to the number of these nerve cells in modern monkeys such as baboons. Researcher sees evidence of more advanced intelligence than previously thought T. rex. In particular, he even acknowledged the ability of tyrannosaurs to transmit information and use tools.
The study was met with great skepticism in the scientific community. Many people wanted to publicly prove Herculano-Ouzel wrong because his article was reported in the media and made a lot of noise. As a result of the war, a group of scientists from different countries was formed, including Germany, Canada and even others. Their rebuttal was published by the journal in late April 2024. Anatomical Registration.
Before that, paleontologists and biologists had been studying the size and anatomy of the brains of prehistoric lizards for decades and drawing conclusions about their possible behavior and lifestyle based on the data obtained. Dinosaur brains are studied with the help of endocasts, which are molds of the inner surface of the skull, and also by the shape of the cavities.
After examining in detail the methods used by Herculano-Ouzel, his opponents showed that they were unreliable. In particular, scientists found that the size of the dinosaur brain and the number of neurons in it, especially in the forebrain, were significantly overestimated. In addition, the authors of the new scientific article emphasized that neuron count alone does not allow to reliably estimate intelligence level.
It is known that the number of neurons increases in proportion to the size of the body. According to the researchers, giants such as tyrannosaurs, which weighed up to 14 tons, needed more neurons to support basic functions of their massive bodies rather than some intellectual tasks, such as using tools.
One of the authors of this rebuttal is Professor of Biological Sciences Douglas R. Wiley (Douglas R. Wylie) from the University of Alberta (Canada) – also said that in the brain of reptiles, neurons are less densely arranged and the number of connections between them is less than in the brain of birds and mammals. However, let us point out that from the perspective of modern science, dinosaurs are closer to birds, which are included in the dinosaur group, than to reptiles.
Because neuron count is an inadequate guide to assessing cognitive function, relying on it to determine the intelligence level of extinct species can lead to wildly inaccurate interpretations, as in the case of Herculano-Ouzel’s study. To obtain reliable results, scientists suggested looking at a broader range of data, including skeletal anatomy, bone histology, fossil analysis, and the behavior of relevant species living today.
“The idea that T. rex could be as intelligent as baboons is fascinating and frightening. <…> However, our research shows that all available data contradicts this idea. Them [тиранозаври] They looked more like intelligent giant crocodiles, which is no less exciting,” the scientists concluded.
Source: Port Altele
