The fossil of what may be one of the earliest baby birds has been found in northeast China.
The fossil, estimated at 121 million years old, is curled up in an egg-shaped space measuring about 1.4 by 0.8 inch (35 by 20 millimeters) — bigger than a robin's egg but smaller than most chicken eggs. The scientists did not find any fossilized shell pieces, however.
The tiny bird had a large skull, feathers and a hardened skeleton, indicating that it was near maturity even though it had not yet hatched.
Birds like this one that develop feathers and can feed on their own by the time they hatch are known as precocious, in contrast to others that hatch naked and helpless.
The bird was found in a layer of shale in Liaoning province by Zhonghe Zhou and Fucheng Zhang of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences.
They described their find in a brief report in Friday’s issue of the journal Science.
They note that while several bird embryos have been reported of a similar age, none had feathers.