Natural Science Forum / Biology / Paleontology / April 2005

Early toolmakers cast off rock-banger image
09 April 2005
Kurt Kleiner

THEY may look crude, but even some of the earliest stone tools were produced with skill and technical sophistication. The finding, based on an analysis of tools found at a 2.34-million-year-old site in Kenya, suggests that early toolmakers' abilities differed from place to place.

The earliest stone tools appear in the fossil record around 2.6 million years ago. This so-called Oldowan phase of toolmaking probably began with an early species of Homo and continued for 1.2 million years. Oldowan tools were simple, sharp-edged stone flakes that a fairly unintelligent hominid could have used for cutting meat. The assumption has been that they were made by mindless, random rock-banging.

But a detailed analysis of tools at Lokalalei 2C, west of Lake Turkana, suggests that hominids at the site were capable of mass production that required forward planning and learning. "It's clear the hominids had some mental image of what they were trying to make," says Brian Richmond, an anthropologist at George Washington University in Washington DC. "You couldn't make a stone tool this way by throwing a rock on the ground or hitting it a couple of times."

French national research organisation (CNRS) scientists Anne Delagnes and Hélène Roche, at Talence and Nanterre respectively, examined more than 2000 stone fragments at the site. The tools were produced by knapping, a process in which the maker uses one rock to chip fragments off another. It is not clear which hominid made the tools: it could have been H. habilis or Australopithecus aethiopicus.

From 285 fragments, Delagnes and Roche were able to piece together 35 of the stones from which the tools had been made, allowing them to replay their construction stroke by stroke (Journal of Human Evolution, DOI: 10.1016/j.jhevol.2004.12.005).

First, the toolmaker selected the raw material, appearing to prefer phonolite, a rock that flakes well and produces sharp edges. A number of pieces of other rock types were found with only a few fragments missing, as if they had been tested and then discarded.

When the toolmaker did find the right raw material, they appeared to know the best way to work it, striking the right spot at the angle needed to give the best flakes. The maker turned the rocks as they struck them, maintaining an even surface that allowed more flakes to be broken off.

Delagnes says the Lokalalei 2C tools differ from those from Lokalalei 1 nearby, which dates from the same era. Here the tools appear to have been made "opportunistically" with no evidence of forethought.

From issue 2494 of New Scientist magazine, 09 April 2005, page 7
http://www.newscientist.com/article.ns?id=mg18624944.200