for National Geographic News
Birds survived the global catastrophe that wiped out their dinosaur relatives due to superior brainpower, a new study suggests.
The idea came from examining a pair of prehistoric seabirds found in southeast England by Victorian-era fossil hunters, according to researchers from the Natural History Museum in London.
The two 55-million-year-old skulls suggest the ancestors of modern birds developed larger, more complex brains earlier than previously thought.
This implies that bird ancestors had a mental edge over non-birdlike dinos and flying reptiles, so they were better able to adapt after the so-called K-T mass extinction event around 65 million years ago, said study co-author Angela Milner.
Some ancient groups of birds did go extinct, she noted, so it wasn't feathers or warm-bloodedness that gave modern birds a leg up.
"It had to be something else, " she said, "and it seems to be this bigger brain."
Big Bird Brains
The study, published last month in the Zoological Journal of the Linnean Society, was based on two specimens from the Natural History Museum's vast fossil collection.
Odontopteryx toliapica belonged to an extinct group of giant, bony-toothed seabirds, while Prophaethon shrubsolei was a prehistoric relative of tern-like tropical seabirds.
Milner and colleagues used CT scans of the skulls to make models of the size and shape of the fossil birds' brains.
(Related: "T. Rex, Other Dinosaurs Had Heads Full of Air" [December 12, 2008].)
What they found is that the ancient bird brains were almost the same size as those in birds alive today. The older noggins also showed early growth of a brain region known as the wulst.
SOURCES AND RELATED WEB SITES