A new examination of the brain size and structure of T.Rex dinosaurs concludes that their intelligence was limited and they behaved more like modern crocodiles and lizards.
In a study published last year, it was claimed that dinosaurs such as T. rex had an exceptionally high number of neurons and were substantially more intelligent than previously assumed. It was claimed that these high neuron counts could directly inform intelligence, metabolism and life history, and that T. rex was rather ape-like in some of its habits. Cultural transmission of knowledge and use of tools were cited as examples of cognitive traits he might have possessed.
However, the new study, published in The Anatomical Record, involving George Hady of the University of Bristol, Dr. Darren Naish (University of Southampton) and led by Dr. Kai Caspar (Heinrich Heine University) with the Dr. Cristian Gutiérrez-Ibáñez (University of Alberta) and Dr. Grant Hurlburt (Royal Ontario Museum) take a closer look at the techniques used to predict both brain size and the number of neurons in dinosaur brains.
The team found that previous assumptions about the size of dinosaur brains and the number of neurons they contained were unreliable.
The research follows decades of analysis in which paleontologists and biologists examined the size and anatomy of dinosaur brains and used this data to infer behavior and lifestyle. Information about dinosaur brains comes from the mineral fillings of the brain cavity, called endocasts, as well as the shapes of the cavities themselves.
The team discovered that the size of his brain (especially the forebrain) and therefore also the number of neurons had been overestimated. Furthermore, they show that neuron count estimates are not a reliable guide to intelligence.
To reliably reconstruct the biology of long-extinct species, the team argues, researchers would need to look at multiple lines of evidence, including skeletal anatomy, bone histology, the behavior of living relatives, and trace fossils.
“The best way to determine the intelligence of dinosaurs and other extinct animals is to use many lines of evidence ranging from gross anatomy to fossil footprints, rather than relying solely on estimates of the number of neurons,” Hady explained in a statement. , from the Bristol School of Earth Sciences.
Dr. Caspar explained: “We maintain that it is not good practice to predict intelligence in extinct species when all we have to go on is neuron counts reconstructed from endocasts.”
“Neuron count is not a good predictor of cognitive performance, and its use to predict intelligence in long-extinct species can lead to very misleading interpretations,” adds Dr. Ornella Bertrand (Institut Català de Paleontologia Miquel Crusafont).
“The possibility that T. rex may have been as intelligent as a baboon is fascinating and terrifying, and has the potential to reinvent our view of the past,” Dr. Naish concluded. “But our study shows how all the data we have goes against this idea. They looked more like intelligent giant crocodiles, and that’s equally fascinating.”
