Thursday, November 15, 2012
Archaeologists Date Stone-tipped Weapons: 500,000 Years Old
This is a ~500,000-year-old point from Kathu Pan 1. Multiple lines of evidence indicate that points from Kathu Pan 1 were used as hafted spear tips. Scale bar = 1 cm.
A collaborative study involving researchers at Arizona State University, the University of Toronto, and the University of Cape Town found that human ancestors were making stone-tipped weapons 500,000 years ago at the South African archaeological site of Kathu Pan 1 – 200,000 years earlier than previously thought. This study, "Evidence for Early Hafted Hunting Technology," is published in the November 16 issue of the journal Science.
Attaching stone points to spears (known as "hafting") was an important advance in hunting weaponry for early humans. Hafted tools require more effort and foreplanning to manufacture, but a sharp stone point on the end of a spear can increase its killing power.
"There is a reason that modern bow-hunters tip their arrows with razor-sharp edges. These cutting tips are extremely lethal when compared to the effects from a sharpened stick. Early humans learned this fact earlier than previously thought," said Benjamin Schoville, a coauthor of this study affiliated with the Institute of Human Origins, a research center of the College of Liberal Arts and Sciences at Arizona State University
Hafted spear tips are common in Stone Age archaeological sites after 300,000 years ago. This study shows that hafted spear tips were also used in the early Middle Pleistocene, a period associated with Homo heidelbergensis, the last common ancestor of Neandertals and modern humans.
"Rather than being invented twice, or by one group learning from the other, stone-tipped spear technology was in place much earlier," said Schoville. "Although both Neandertals and humans used stone-tipped spears, this is the first evidence that this technology originated prior to or near the divergence of these two species."
"It now looks like some of the traits that we associate with modern humans and our nearest relatives can be traced further back in our lineage," said Jayne Wilkins, lead author from the University of Toronto. "This changes the way we think about early human adaptations and capacities before the origin of our own species."
Point function was determined by comparing wear on the ancient points to damage inflicted on modern experimental points used to spear a springbok carcass target with a calibrated crossbow. This method has been used effectively to study weaponry from more recent contexts in the Middle East and southern Africa.
"When points are used as spear tips, there is a lot of damage that forms at the tip of the point, and large distinctive fractures form. The damage on these ancient stone spear points is remarkably similar to those produced with our calibrated crossbow experiment, and we demonstrate they are not easily created from other processes," said coauthor Kyle Brown, a skilled stone tool replicator from the University of Cape Town.
The points were recovered during 1979 excavations by Peter Beaumont of the McGregor Museum, Kimberly, South Africa.
In 2010, a team directed by coauthor Michael Chazan from the University of Toronto reported that the point-bearing deposits at KP1 dated to around 500,000 years ago using optically stimulated luminescence and U-series/electron spin resonance methods. The dating analyses were carried out by Naomi Porat, Geological Survey of Israel, and Rainer Grün, Australian National University.