Several million ago, science assumes, there was a mass extinction of countless species, mainly dinosaurs. Despite this, there are still traces of past lives, and now scientists have discovered why some birds survived despite this, and they attribute this to having more developed brains.
Researchers at the University of Texas at Austin (USA) announced this Friday (30) the discovery of a possible explanation for how a branch of ancient dinosaurs survived and became the current birds that exist across the planet.
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A study of a recently discovered prehistoric bird fossil found that the way the brain developed could be the reason that bird ancestors survived the mass extinction that wiped out all other dinosaurs.
“Birds today have more complex brains than all other known animals, with the exception of mammals,” said the study’s lead author, Christopher Torres. “This new fossil finally allowed us to test the idea that brains played a huge role in bird survival.”
The fossil is about 70 million years old and was found with a nearly intact skull, something very rare for this type of discovery, allowing scientists to compare the prehistoric bird with today’s birds. The results were published this Friday in the journal Science Advances.
This is the new specimen of a prehistoric bird called Ichthyornis, which lived in what is now Kansas (USA) during the late Cretaceous period and went extinct at the same time as the non-avian dinosaurs.
The species had a mix of avian and non-avian dinosaur features, such as a jaw with teeth but ending in a beak. The intact skull allowed scientists to analyze the brain more accurately. Using CT scans, they used Ichthyornis’ skull as a mold to make a 3D replica of the brain, which was compared to similar replicas of modern-day birds and other dinosaurs.
The researchers found that Ichthyornis’ brains were more like those of non-avian dinosaurs than those of modern birds. In particular, the cerebral hemispheres—where more advanced cognitive functions such as speech, thinking, and emotion occur in humans—are more developed in today’s birds than in Ichthyornis. The pattern suggests that these functions may be linked to survival during mass extinction.
“If a brain function affects the probability of survival, we expect it to be present in species that still exist today, but absent in those that have gone extinct, such as Ichthyornis,” explained Torres. “That’s what we can see here.”
The search for skulls of prehistoric birds and avian dinosaurs is one of the main challenges for paleontologists, due to the fragility of bird skeletons, which rarely survive fossilization in one piece.
Well-preserved skulls are even rarer, and at the same time, they are essential for scientists to be able to understand what the brains of living animals were like.
“Ichthyornis is key to unraveling this mystery,” said Julia Clarke, professor of geosciences at the University of Texas and co-author of the study. “This fossil brings us much closer to answering some persistent questions about today’s birds and how they survived amid the end of the dinosaurs.”
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