>From yesterday's New York Times (front page article):
In a discovery with profound implications for the study of early
human history,scientists digging in the republic of Georgia have
found 1.7-million-year-old fossil human skulls that show clear signs
of African ancestry and so may represent the species that first
migrated out of Africa.
<snip>
The findings contradicted the theory that human ancestors left
Africa soon after they
invented better stone axes and other tools of what archaeologists
call the Acheulean culture. The more than 1,000 stone tools found in
the sediments with the two skulls were all pre-Acheulean, crudely
chipped cobbles that had been made since human ancestors began
knapping stone tools about 2.5 million years ago.
<snip>
Dr. Susan C. Anton, a paleoanthropologist at the University of
Florida who was a member of the discovery team, said that by this
time human ancestors had become more carnivorous and their diets
pushed them to expand their home range to match the wider ranges of
the animals they preyed on.
"With the appearance of Homo, we see bigger bodies that require more
energy to run, and therefore need these higher quality sources of
protein as fuel," Dr. Anton said of the adaptation to meat-rich
diets.
As long as early human ancestors had smaller bodies and brains, Dr.
Tattersall said, they lived mainly on plants and confined themselves
to a limited range at the edge of forests, not too deep in or too
exposed far out on the savanna. Once they had stronger bodies and
high-protein meat diets, they were able to spread out geographically
and ecologically.
<snip>
He said the implications of the new findings for human dispersal
from Africa supported an idea he and his wife, Dr. Pat Shipman, an
anthropologist, proposed in 1989. They suggested that once the more
apelike australopithecines evolved into the genus Homo and became
carnivorous, they were forced to expand their home territory.
"Herbivores are restricted to where the plants are that they eat,"
Dr. Walker said. "Carnivores are not so restricted. Meat is meat,
and you often have to travel far to find it."
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