Ancient tools indicate chimps' stone age
The
first prehistoric evidence for a "chimpanzee stone age" has been
uncovered by archaeologists working in an African rainforest. Primitive
stone hammers and anvils, dating from 4,300 years ago, were excavated
(dug out) from pits at three sites in the Tai national park in Ivory
Coast.
The tools, used to crush and crack food, are too large for humans to
have wielded (handled) with ease, and showed traces of starch from
varieties of nuts that were staples of the chimp diet, but avoided by
humans.
The discovery suggests that from ancient times, chimpanzees used
rudimentary (basic) technology and
handed the skills down to later generations. The flood plain where the
stone fragments were uncovered was not widely occupied by humans at the
time, leading the researchers to suspect that early tool use was not
learned from humans, but may have been passed on to chimps and humans
alike from a more primitive ancestor.
"It's not clear whether we invented this kind of stone technology, or
whether both humans and great apes inherited it from a common forebearer",
said Julio Mercader from the University of Calgary, who led the study.
"There weren't any farmers living in this region 4,300 years ago, so
it's unlikely the chimpanzees picked it up by imitating villagers". The
study was published in the journal Proceedings of the National Academy
of Sciences.
He added: "We used to think that culture and, above anything else,
technology was the exclusive domain of humans, but this is not the
case".
The researchers believe the intact tools would have ranged from less
than 200g to nearly 7 kg (7oz to 15 lb). Tests revealed the stones had
most likely been used to crack open five varieties of nuts, four of
which are thought to have been eaten by chimpanzees, but not humans.
The technique was more subtle than simply smashing the nut between
two rocks, according to the researchers. Some nuts required a force of
more than a tonne to crack them open, and a more complex technique was
needed to do so without destroying the nut inside.
Huw Barton, a co-author on the study at Leicester University, said
the finding raised the suggestion that tool use among chimpanzees may
have progressed, at least for a while, in parallel with human usage.
"At the moment, we know chimpanzees' tool use goes back at least
4,300 years, but what if it goes back much further? Who knows what we'd
find!"
The Guardian |