Dinosaurs smart reptiles but not as intelligent as monkeys, findings contradict earlier ones

PTI

New Delhi, April 29

Dinosaurs were “more like smart giant crocodiles” but not as intelligent as monkeys as an earlier study had found, according to new research.

In a study published in January 2023, neuroscientist and author Suzana Herculano-Houzel of Vanderbilt University, US, had said that brains of theropod dinosaurs, a species of which is T. rex, had neurons comparable to those in the brains of monkeys and baboons.

Dinosaurs like T. rex, or Tyrannosaurus rex, had an exceptionally high number of neurons, “which would make these animals not only giant but also long-lived and endowed with flexible cognition, and thus even more magnificent predators than previously thought,” the author wrote in the study published in the Journal of Comparative Neurology.

In the latest research, an international team of palaeontologists, behavioural scientists and neurologists re-examined the brains of dinosaurs, including T. rex, and found them to behave more like reptiles.

They were more like “smart giant crocodiles,” according to study author Darren Naish from the School of Biological Sciences, University of Southampton, UK.

The team found that the size of the dinosaur brains had been overestimated, along with neuron counts, and showed that gauging the intelligence of a species based on neuron count estimates is not reliable. The findings are published in The Anatomical Record journal.

“Neuron counts are not good predictors of cognitive performance, and using them to predict intelligence in long-extinct species can lead to highly misleading interpretations,” said study author Ornella Bertrand from Universitat Autònoma de Barcelona, Spain.

The research follows along the lines of decades of analysis in which palaeontologists and biologists have examined dinosaur brain size and anatomy, and used these data to infer behaviour and lifestyle, the authors said.

Information on dinosaur brains comes from mineral fillings of the brain cavity, termed endocasts, as well as the shapes of the cavities themselves, they said.

“We argue that it’s not good practice to predict intelligence in extinct species when neuron counts reconstructed from endocasts are all we have to go on,” said lead researcher Kai Caspar from Heinrich Heine University, Germany.

They said that to reliably reconstruct the biology of long-extinct species, researchers should look at multiple lines of evidence, including skeletal anatomy, bone histology (study of the microscopic structure of tissues) and the behaviour of living relatives and trace fossils.

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