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Dinosaurs were less intelligent than modern day monkeys

The captivating image of dinosaurs – especially apex predators like Tyrannosaurus rex – as cunning, highly intelligent creatures has long been a staple of both scientific inquiry and popular imagination.

But a new study led by the University of Bristol is shaking the foundations of this long-held belief, suggesting that these prehistoric giants might not have been the intellectual powerhouses we envisioned.

Previous claims on intelligent dinosaurs

The study has shed light on the cognitive abilities of dinosaurs. Previous research hinted at exceptionally high neuron densities in the brains of certain species. These findings led to compelling hypotheses suggesting that dinosaurs might possess intelligence levels similar to primates.

This revelation opened the possibility of remarkably complex behaviors, previously considered unique to mammals. Scientists began to envision dinosaurs engaging in behaviors such as tool use, passing down knowledge within their groups, and even demonstrating rudimentary problem-solving skills.

These implications have the potential to significantly transform our understanding of dinosaur behavior and evolution as a whole.

Neurons determine dinosaur intelligence

An international team of experts, including paleontologists, behavioral scientists, and neurologists, conducted a thorough analysis of the techniques used to estimate dinosaur brain size and the number of neurons within those brains.

The study highlighted significant issues with previous assumptions. The team’s findings suggest that earlier studies may have overstated both the brain size and the density of neurons. This casts doubt on the previously assumed direct link between high neuron counts and advanced intellectual abilities.

“We present revised estimates of encephalization and telencephalic neuron counts in dinosaurs, which we derive from phylogenetically informed modeling and an amended dataset of endocranial measurements. For large-bodied theropods in particular, we recover significantly lower neuron counts than previously proposed,” wrote the study authors. 

“Furthermore, we review the suitability of neurological variables such as neuron numbers and relative brain size to predict cognitive complexity, metabolic rate and life history traits in dinosaurs, coming to the conclusion that they are flawed proxies for these biological phenomena.”

“Instead of relying on such neurological estimates when reconstructing Mesozoic dinosaur biology, we argue that integrative studies are needed to approach this complex subject.”

Dinosaur capabilities and limitations

How do we understand the minds of extinct creatures? The researchers emphasized the importance of a multi-faceted approach.

“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 estimates alone,” explained study co-author Hady George.

Scientists can use multiple sources of information: skeletal anatomy, bone structure analysis, comparisons with the behavior of modern-day relatives, and even the trace fossils left behind by these ancient creatures. Together, these tools paint a more complete picture of dinosaur capabilities and potential limitations.

Highly intelligent reptiles

While it may seem less thrilling to imagine dinosaurs without primate-level intellect, this study offers a compelling shift in perspective. “They were more likely akin to highly intelligent reptiles, which presents a different, but equally fascinating picture of their capabilities.” explained Dr. Darren Naish, co-author of the study.

Dinosaurs were not failures; they were incredibly successful within the context of their evolutionary journey. This means we should focus on their strengths as dinosaurs instead of comparing them to mammals who evolved along a different path millions of years later.

Importantly, dinosaurs were the apex lifeforms for a vast swath of Earth’s history. They weren’t competing with mammals but rather occupied the dominant ecological niches on the planet. Their success depended on the ability to evolve traits suited to their environment.

Dinosaurs were intelligent for their time

Dinosaurs thrived for millions of years because they weren’t merely surviving, but mastering their environments. This mastery was achieved through a stunning array of adaptations. Their physical adaptations, like immense size, protective armor, or specialized teeth, are easily visible in fossils.

They also evolved complex behavioral adaptations such as herding for safety, migration to follow resources, and intricate nesting behaviors to care for their young. Additionally, their physiological adaptations, such as unique metabolic processes or highly specialized sensory systems, allowed them to exploit specific ecological niches.

Traditionally, judging dinosaurs as “failed mammals” implies a narrow view of evolution where our own intelligence is the only worthwhile endpoint. A more insightful approach recognizes that dinosaurs were incredibly successful, evolving within the distinct challenges and opportunities of their specific eras.

Dinosaurs represent a unique evolutionary trajectory, demonstrating the remarkable ability of lifeforms to adapt and flourish within Earth’s ever-changing environment.

The study is published in the journal The Anatomical Record.


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