T. Rex Intelligence Debate: New Study Challenges Neuron Count Claim

A recent study published in The Anatomical Record on April 26, 2024, disputes the claim made by Suzana Herculano-Houzel in 2023 that Tyrannosaurus rex had 3 billion neurons, suggesting it was as smart as a baboon. The new study, conducted by an international team of paleontologists, behavioral scientists, and neurologists, argues that T. rex's intelligence was likely closer to that of modern-day crocodiles, with a brain size and neuron count significantly lower than initially proposed.

Why this matters: This study's findings have significant implications for our understanding of dinosaur intelligence and behavior, and challenge our assumptions about the cognitive abilities of ancient species. Furthermore, this debate highlights the importance of rigorous scientific inquiry and the need for ongoing research to refine our knowledge of the natural world.

The study re-examined brain sizes and structures in dinosaurs, concluding that T. rex brain size had been overestimated, especially the forebrain. The team found that T. rex neuron counts were likely way off base, and that the dinosaur's intelligence was more comparable to reptiles like crocodiles and lizards. The study emphasized the importance of considering multiple lines of evidence, including gross anatomy, fossil footprints, and bone histology, rather than relying solely on neuron number estimates.

Herculano-Houzel's 2023 study had suggested that T. rex might be able to pass on knowledge to their young and even use tools, based on neuron counts comparable to those of baboons. However, the new study's team members, such as Hady George and Cristian Gutiérrez-Ibáñez, argue that neuron count estimates are not a reliable guide to intelligence and that brain tissue does not always fill the entire skull.

The debate highlights the limitations of reconstructing the biology of an extinct animal, acknowledging that behavior is not fossilized and cannot be directly observed. The findings have implications for our understanding of dinosaur intelligence and behavior, suggesting that T. rex may not have been as intelligent as previously thought.

Zoologist Kai Caspar emphasized, "There is no reason to assume that T. rex had primate-like habits... What needs to be emphasized is that reptiles are certainly not as dim-witted as is commonly believed." University of Maryland palaeontologist Thomas Holtz added, "Given the brain size we found for it, Tyrannosaurus probably occupied a level of intelligence we don't see in the modern world... More intelligent than crocodilians, but less intelligent than typical living birds and mammals."

The new study, published inThe Anatomical Record, presents a compelling challenge to the previous claim about T. rex's intelligence. As the scientific community continues to investigate and debate this topic, it underscores the complexities and uncertainties inherent in understanding the cognitive abilities of long-extinct creatures like the iconic Tyrannosaurus rex.

Key Takeaways

• New study disputes T. rex's intelligence, suggesting it's closer to crocodiles than baboons.
• T. rex brain size and neuron count were likely overestimated in previous study.
• Neuron count is not a reliable guide to intelligence, and brain tissue doesn't always fill the skull.
• T. rex intelligence is likely more comparable to reptiles, not primates or birds.
• Study highlights limitations of reconstructing extinct animal biology and behavior.