Large theropods were as smart as reptiles but not as intelligent as monkeys, according to new research led by University of Bristol paleontologists.
In a study published last year, Vanderbilt University paleontologist Suzana Herculano-Houzel claimed that dinosaurs like T. rex had an exceptionally high number of neurons and were substantially more intelligent than assumed.
She claimed that these high neuron counts could directly inform on intelligence, metabolism and life history, and that T. rex was rather monkey-like in some of its habits.
“The Late Cretaceous North American theropod dinosaur T. rex is a superlative predator, being among the largest, heaviest, and most powerful (in terms of bite force) terrestrial carnivores of all time,” said University of Bristol’s Dr. Hady George and colleagues.
“Recently, Dr. Herculano-Houzel proposed that anthropoid primate-level intelligence should be added to T. rex’s already impressive predatory resume based on high estimates for the number of neurons in its forebrain.”
“This conclusion emerged from a paradigm whereby neurological variables estimated from endocasts can, so it is claimed, be used to infer metabolic parameters, behaviors, and longevity in fossil species.”
In their new study, Dr. George and co-authors took a closer look at techniques used to predict both brain size and neuron numbers in dinosaur brains.
They found that previous assumptions about brain size in dinosaurs, and the number of neurons their brains contained, were unreliable.
This new research follows decades of analysis in which paleontologists and biologists have examined dinosaur brain size and anatomy, and used these data to infer behavior and lifestyle.
Information on dinosaur brains comes from mineral infillings of the brain cavity, termed endocasts, as well as the shapes of the cavities themselves.
The authors found that their brain size had been overestimated — especially that of the forebrain — and thus neuron…
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