DAVIS, Calif., Aug. 14 (UPI) -- A U.S. anthropologist said chance, not evolution, best explains why the modern human skull looks so different from its Neanderthal relatives.
"For 150 years, scientists have tried to decipher why Neanderthal skulls are different from those of modern humans," said University of California-Davis Assistant Professor Tim Weaver. "Most accounts have emphasized natural selection and the possible adaptive value of either Neanderthal or modern human traits.
"We show that, instead, random changes over the past 500,000 years or so … are the best explanation for these differences."
Weaver, University of Illinois Assistant Professor Charles Roseman and paleoanthropologist Chris Stringer of the Natural History Museum in London compared cranial measurements of 2,524 modern human skulls and 20 Neanderthal specimens.
The scientists concluded Neanderthals didn't develop protruding mid-faces as an adaptation to icy Pleistocene weather or the demands of using teeth as tools and the retracted faces of modern humans aren't an adaptation for language, as some anthropologists have proposed.
Instead, random "genetic drift" is the likeliest reason for the skull differences.
The study is reported in the Journal of Human Evolution.
