Achi news desk-
Visitors look at a Tyrannosaurus rex skeleton at the French National Museum of Natural History in Paris in 2018.Philippe Wojazer/Reuters
Guessing even the physical appearance of a dinosaur – or any extinct animal – based on its fossils is a difficult proposition, with so much uncertainty involved. Assessing dinosaur intelligence, considering the myriad factors that contribute to that trait, is exponentially more difficult.
A study published last year by Vanderbilt University neuroscientist Suzana Herculano-Houzel that evaluated the intelligence of Tyrannosaurus rex, focusing on estimated brain size and the number of brain neurons, similar to that of primates – specifically a baboon – caused a stir in scientific circles . .
Now, an interdisciplinary scientific team has published a study refuting, questioning Herculano-Houzel’s methodology and challenging her evaluation of the smarts of T. rex and other large dinosaur predators in the clade of dinosaurs known as theropods.
Instead, they suggested a more holistic approach to assessing the brain of Tyrannosaurus or any extinct animal, with brain size and neuronal count considered alongside other factors such as an animal’s anatomy and ecology, data from living relatives, and fossil evidence about how he moved around and fed which offers an insight into his life.
“Our key findings are that the brains of most dinosaurs, including T. rex, are comparable in size to the brains of living reptiles, such as crocodiles and alligators. Moreover, their neuron numbers were probably not exceptional, especially for animals of their body mass,” said zoologist Kai Caspar of Heinrich Heine University in Germany, who studies the behavior of living animals and he was the lead author of the study published this week in The Anatomical Record Journal.
“What needs to be emphasized is that reptiles are certainly not as dim as is commonly believed,” added Caspar. “Their behavior can be very complex, and the experimental data we have suggests many cognitive similarities between them, mammals and birds. So although there is no reason to assume that T. rex had primate-like habits, it was certainly a behaviorally sophisticated animal.”
Herculano-Houzel said she stands by her findings and called the new analysis flawed.
“The only thing that is debatable is what was already at the time of my study: what the brain size of dinosaurs actually was. Even then, we’re talking about the difference between a T. rex brain and the size of a baboon or a monkey,” says Herculano-Houzel.
“Their conclusion hinges on one very important point: whether theropods like T. rex shared their relationship (brain-to-body size) with their warm-blooded cousins the ostrich and chicken, or with their most distant living relatives, crocodiles. I said the former, because I compared theropods to ostriches and chickens; they now have the last say,” added Herculano-Houzel.
Caspar said the comparison with modern birds was also an integral part of the new study.
There are problems with trying to measure intelligence from brain neuron counts, says Caspar.
“The first hurdle is to estimate the actual brain size of the extinct animal in question. This is not a trivial question in dinosaurs. While the brain fills almost the entire skull cavity in birds and us mammals, this is not the case for reptile species, whose brains fill only about 30-50% of the skull cavity,” said Caspar.
“The 2023 study assumed that there was 100% fill in dinosaurs like T. rex, and that was certainly not the case,” added Caspar.
It is not known how dense the neurons were in dinosaur brains, says Caspar.
“However, when we look at living animals, we see that neuron count is not a good indicator of intelligence in the first place, even though that might seem intuitive at first glance,” added Caspar.
The dinosaurs, apart from their bird descendants, disappeared 66 million years ago after an asteroid hit the Earth. In two centuries of scientific study, dinosaurs are coming into better focus, although plenty of uncertainty remains about Tyrannosaurus and the others.
“Given the size of the brain we found, Tyrannosaurus probably possessed a level of intelligence we don’t see in the modern world: more intelligent than crocodiles, but less intelligent than typical living birds and mammals ,” said University of Maryland paleontologist Thomas Holtz , co-author of the new study.
“Intelligence is one of the hardest things to measure even in modern animals, and many of our common assumptions don’t really hold up when you actually examine what animals are real doing it in the real world,” said Holtz.
“So when we try to estimate the intelligence and cognition of ancient animals, we’re going to have some difficulties. It would be nice if we could estimate just one number and solve the whole complexity of an animal’s biology and lifestyle, but that’s not how nature works.”
Ad blocking test (Why?)
Source link
The post Tyrannosaurus rex at the center of the debate over dinosaur knowledge appeared first on Canada News Media.
