A T. rex skeletal cast at the Senckenberg Museum Frankfurt, Germany. T. rex lived at the end of the Cretaceous (about 66 million years ago) and was exclusive to western North America. Credit: Kai R. Caspar
Key points:
- A previous study suggested that dinosaurs had a high number of neurons and were as intelligent as monkeys.
- New research has refined the prior technique and revealed that both dinosaur brain size and neuron counts were overestimated.
- A more accurate combination of methods showed that the T. rex may not have been as intelligent as a baboon, but instead was similar to a smart giant crocodile.
Last year, a study suggested that dinosaurs like T. rex had an exceptionally high number of neurons and were more intelligent than previously assumed. However, new research, published in The Anatomical Record, examines the techniques used in the previous study and reveals that the findings were unreliable.
In the original work, scientists used mineral infillings of the brain cavity and the shape of the cavities themselves. In the current study, to reliably reconstruct the biology of extinct species, researchers examined multiple lines of evidence, including skeletal anatomy, bone histology, the behavior of living relatives, and trace fossils.
Researchers found that both the dinosaur brain size and neuron counts had been overestimated. Importantly, they also found that neuron count estimates are not a reliable guide to determine intelligence.
“Determining the intelligence of dinosaurs and other extinct animals is best done using many lines of evidence ranging from gross anatomy to fossil footprints instead of relying on neuron number estimate alone,” explained study author Hady George of the University of Bristol.
The team used their accurate combination of methods to show that the T. rex may not have been as intelligent as a baboon, but instead was similar to a smart giant crocodile. Looking ahead, the team hopes research will shift away from neuron counts as they contribute to misleading interpretations of intelligence.