- WASHINGTON - Old bones may
tell the tale of how short, stocky, hairy Neanderthals were supplanted
in Europe some 30,000 years ago by thinner, taller, more adaptable modern
humans, scientists say. By studying the chemicals that remained in the
bones of the earliest modern humans, scientists discovered that their diet,
which included fish and fowl as well as large mammals, may have given them
the edge over the Neanderthals, who favored an all-big-mammal menu.
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- Both Neanderthals and humans needed to pack on weight,
because Europe was a much colder place then, with glaciers covering the
British Isles from time to time and Scandinavia periodically under ice,
according to Michael Richards, a researcher at the University of Bradford
in Britain.
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- A specialist in the prehistoric diet, Richards said by
telephone that a study published in the current Proceedings of the National
Academy of Sciences looked at the bone chemistry of Neanderthals and the
modern humans that coexisted and eventually supplanted them.
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- Previously, scientists had generally looked at old stone
tools and animal bones found near human remains to get an idea of what
early modern humans and their ancestors ate. But Richard said this method
could give equivocal or incomplete results, while bone chemistry provided
clearer clues.
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- "The bones are made up of the foods you eat, so
they're a direct measure of diet," Richards said. And while the ancient
bones might degrade in some cases, scientific analysis showed that the
bones used in this study did not, he said.
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- SLIM PICKINGS
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- The pickings were rather slim: scientists worked with
data from the bones of five Neanderthals and nine skeletons of early modern
humans, all from a period some 20,000 to 30,000 years ago.
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- This was near the end of the Neanderthals' time in Europe,
and the beginning of the modern humans' time, with an overlap of about
10,000 years. Before this, Neanderthals had lived in this area starting
about 120,000 years ago, Richards said.
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- The key to the modern humans' survival appeared to be
a more diverse diet, which gave them more choices in lean periods.
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- Neanderthals spent most of their lives hunting and eating
large mammals, such as red deer, reindeer and sometimes mammoth, Richards
said. This diet kept their heavy muscles going and enabled them to survive.
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- But when early modern humans moved into Europe, probably
from Africa, they brought an appetite for the same large herbivores that
the Neanderthals wanted, putting pressure on supply.
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- However, while Neanderthals only wanted the land mammals,
the modern humans also caught fish and wild birds to supplement their diet.
The bone analysis, based on comparing levels of the isotopes carbon 13
and nitrogen 15, indicated that the Neanderthals relied almost exclusively
on red meat, while the humans derived 10 to 50 percent of their dietary
protein from fish and fowl.
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- Vegetables and fruits played little role in the diets
of Neanderthals and early modern humans, he said. "They were eating
some (vegetables and fruits), but it was not enough to show up in their
bone chemistry," Richards said.
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- The fish-and-fowl diet meant humans could turn to a wider
spectrum of nutritional sources when the hunting was poor, Richards said.
"My take on this is this is why Neanderthals were extinct while modern
humans were much more successful," he said.
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- Richards acknowledged that there were other hypotheses
on why the Neanderthals died out. Some scientists - including one of Richards'
colleagues in the new research, Erik Trinkaus of Washington University
in St. Louis - have theorized that the species interbred with modern humans
and might have faded into a common gene pool.
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- Stephen Cunnane, a professor of nutrition at the University
of Toronto, suggested that the new research supported the idea that a concentration
on fish food helped boost the brain power of modern humans. Such food is
known to contain higher levels of DHA, a fatty acid proven to enhance brain
and eye development.
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- "I am delighted that other researchers are now finding
supporting evidence" for the theory, Cunnane said. "We know that
DHA was important in the development of the larger brain."
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- He said studies from Africa, the ancestral land of modern
humans, showed that human beings may have evolved near the coastline, where
seafood was plentiful, and then migrated later to the inland African plains
and eventually to the rest of the world.
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- "You don't need a big brain to collect mussels and
clams, but living on them gives you the excess energy and nutrients that
can be directed toward brain growth," Cunnane said in a statement.
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- The Associated Press and Reuters contributed to this
report.
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