Which Came First: the Bird or the Bird Brain?
New research using CT scans indicate a flight-ready brain was present in some non-avian dinosaurs
Source Newsroom: New York Institute of Technology
Newswise — Old Westbury, N.Y. (July 31, 2013) — Many dinosaurs had large “flight-ready” brains long before some of them soared the skies as ancestors of modern birds, according to new research published today in Nature by a New York Institute of Technology scientist and three other researchers.
Assistant Professor Gaberiel Bever, Ph.D., of the College of Osteopathic Medicine, was part of a team that completed one of the first comprehensive studies detailing the relatively large size of birds’ brains and how they evolved.
The “bird brain” cliché is actually a misnomer; bird brains, like those of mammals, are relatively large compared to body size, Bever said, adding that the study’s conclusions also refute the common notion that the large forebrain of birds evolved as part its flight system.
“A close connection today doesn’t mean that the brain and fly behavior evolved together as an integrated system,” said Bever, who is also a research associate in the Division of Paleontology at the American Museum of Natural History. “Our study establishes that dinosaurs had these big brains before they could fly. Before they took to the air, they had a flight-ready brain: a brain with the neuronal capacity needed to navigate a three-dimensional space.”
Bever and colleagues from the American Museum of Natural History, Columbia University and the University of Texas at Austin used high-resolution computed tomographic (CT) scans and digital software to reconstruct three-dimensional models of the brains of the 100-million-year old Archaeopteryx, a winged species generally considered to be the earliest bird.
"If Archaeopteryx had a flight-ready brain, which is almost certainly the case given its morphology, then so did at least some other non-avian dinosaurs," said Amy Balanoff, a research associate at the American Museum of Natural History and a postdoctoral researcher at Stony Brook University.
The researchers also sampled living groups of birds and other extinct non-avian dinosaurs.
“We not only looked at the brain as a whole but we were able to divide the brain up into its different regions,” said Bever. “That allowed us to estimate how those different regions changed relative to each other, not only to body size. The forebrain is where a lot of the action occurs.”
Bever’s future studies will focus on answering more questions about bird brain evolution.
“It’s a difficult question to answer why anatomical structures evolved originally. How they are used by living creatures often doesn’t tell you the whole story” he said. “We’re still working on what factors may have been driving the original enlargement of the bird brain. But it doesn’t appear to be flight or the requirements of flight. That brain was in place before flight.”
The study was funded in part by the National Science Foundation.
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