Discovery in Ethiopia sheds new light on history of
man
Abram Katz , Register Science Editor 10/22/2003
Michael Rogers was scaling a slope in Ethiopia when he
spotted the earliest evidence that tools were used to
butcher animals 2.3 million years before the first
modern humans appeared on earth.
The small angular rock that Rogers found was chipped
from a stone blade.
This significant find shows that our hominid ancestors
were far more capable than previously thought.
The trove of stone flakes and associated bones also
suggests that Homo sapiens evolved a large brain in
response to growing manual dexterity, rather than the
other way around.
Rogers, assistant professor of anthropology at
Southern Connecticut State University and his
international colleagues were exploring the Gona
region of the Ethiopian badlands in 2000 when the
tools and bones were discovered.
The research was published in the September Journal of
Human Evolution.
"One of the main goals is to find the maker of those
tools," Rogers said.
The earliest human-like primates found so far are 2 to
3 million years old.
Modern humans did not inhabit the plains of Africa
until about 200,000 years ago.
"We traditionally thought that the hominid
Australopithecus didn’t use tools. This may have to
change," Rogers said.
Two species of Australopithecus lived about 2.3 to 2.8
million years ago in the Gona area.
"There’s no reason Australopithecus couldn’t have used
tools. Modern chimpanzees use sticks and stone … to
crack nuts," Rogers said.
Whoever chopped up animals at Gona 2.6 million years
ago did not pick up the first handy rock.
Stone flakes show that the Gona hominids intelligently
selected stones and fashioned them into sharp edges.
"They obviously had the capability to know good stones
from bad," Rogers said.
They selected chert, aphanamitic lava and trachyte,
which split naturally into pieces with sharp edges.
Finding the bones mingled with the stones is
especially significant, Rogers said.
Geologists had previously found bones with tool marks
— but no tools, and stone tools without bones.
"This is the first site of bones and stones of this
age," he said.
The site, which is only about 4 meters by 1 meter, was
located on the banks of a prehistoric channel.
Strata of rock that gradually formed above the site
include a 20-foot band of volcanic ash, which can be
precisely dated.
Analysis put the excavation site at 2.58 million years
ago.
"Bone preservation is very poor," Rogers said, so no
cut marks were evident.
However, a stone flake was found embedded in one of
the bones. The largest bone belonged to a 200-pound
mammal of some kind.
Rogers said the initial flake was lying on the
surface.
"Purposeful flaking is not hard to recognize. I saw a
dozen of them," he said.
Rogers said the site contained a wide range of rocks
and fragments, ruling out the possibility that the
materials were washed together in a prehistoric
stream.
"Finding a hominid that goes with the tools is the
next step," Rogers said.
That will depend largely on luck. "We know what to
look for and where to look," he said.
If the tool chippers turns out to be Australopithecus,
then that will be evidence that fabrication of tools
came before increased brain capacity, Rogers said.
That would answer a longstanding "chicken and egg"
question about whether bigger brains led to tool
making, or tool making resulted in Homo sapiens’ big
brain.
"Any future find will reshape what we know," Rogers
said.
Meanwhile, all of the bones, tools and stone flakes
are in storage in Addis Ababa, Ethiopia.
Rogers was part of the international Gona
Paleoanthropological Research Project, led by Sileshi
Semaw, an Ethiopian anthropologist at Indiana
University
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