Chimps give insight into human tool use
The first ever archaeological excavation of a tools used by chimpanzees may help push back the date that humans first used tools.
The study by Christophe Boesche, a primatologist at the Max Planck Institute for Evolutionary Anthropology in Germany, Julio Mercader, a specialist in rainforest archaeology from the George Washington University and colleagues appears in this week's Science.
The team studied archaeological evidence from chimpanzees in a remote West African rainforest where the chimps use stones and branches as hammers to crack open different types of nuts when foraging.
The repeated occupation of the same site over many seasons allowed for the cracked nut shells and stone pieces that break off of the hammers to build up.
The researchers unearthed materials including more than 479 stone pieces that may have flaked off when smashed on tree roots the chimpanzees used as anvils.
In addition to the possibility of tracing ape culture back in time, the scientists also believe the research will open up new ways of interpreting some early hominid, or human, sites.
"Some of the stone by-products of chimpanzee nut-cracking are similar to what we see left behind by some of our early ancestors in East Africa during a period called the 'Oldowan,'" said Mercader.
The results of the team's research indicates the possibility that some of the technologically simplest Oldowan sites could be re-interpreted as nut-cracking sites.
"We know that flaked stone tools were used 2.5 million years ago, but stone tools may have been used by hominids as long as 5 million years ago," said co-author Melissa Panger, who studies primate tool use at George Washington.
"If we look for assemblages of stone pieces like those we have found left behind by the chimpanzees, we can infer that those assemblages may relate to tool use, even if we don't have the tools."
Until now, archaeologists have focused on buried cultural remains left behind by our ancestors, but with the excavation of the chimpanzee stone tool site, scientists now know that humans are not the only animals whose behavior creates archaeological sites.
This discovery opens up a new territory for archaeology, primatology, and paleoanthropology.
The project was primarily supported by the Max-Planck Institute of Evolutionary Anthropology in Germany. Christopher Boesch, an expert in chimp behaviour at the Institute was the other author of the paper.