The hunt for food led hominins to cast the first stone half a million years ago ? 200,000 years earlier than we thought. Archaeologists have found the oldest evidence yet of stone-tipped spears.
The new discovery in South Africa suggests that it was neither our species nor Neanderthals that pioneered the use of such spears, but our shared ancestor Homo heidelbergensis.
We already knew that Homo heidelbergensis could fashion wooden spears ? a 500,000-year-old horse shoulder blade from Boxgrove, UK, has a semicircular hole in it that suggests it was pierced by a spear. "But the hole's bevelled edges and circular shape are not suggestive of a stone-tipped weapon," says Jayne Wilkins at the University of Toronto in Ontario, Canada.
Stone points used on spears had been found only at sites that date back no more than 300,000 years, and that are associated with Neanderthals or archaic members of our species.
That gives huge significance to a new discovery by Wilkins and her colleagues in 500,000-year-old deposits at Kathu Pan in South Africa. The team unearthed a hoard of stone points, each between 4 and 9 centimetres long, that they think belonged to the earliest stone-tipped spears yet found. The stone points are the right shape and size for the job, and some have fractured tips that suggest they were used as weapons.
Crucially, the points show signs of having been resharpened to maintain their symmetry. That is characteristic of spear tips and not of handheld cutting tools; the latter typically become less symmetrical with use because only the side of the tool used for cutting is kept sharp.
The find does more than simply extend the prehistory of stone-tipped spears ? it puts those first spears firmly in the hands of Homo heidelbergensis, says Wilkins. Modern foragers use such tools to take down large game as part of cooperative, strategic hunts. Perhaps our ancestor did so too.
"The spears are evidence for the deep accumulation of hunting behaviours in our lineage," says Wilkins. Use of the spears may have developed as the brain of Homo heidelbergensis increased in size, she says.
Paola Villa at the University of Colorado Museum in Boulder agrees with the findings. She points out that at a 350,000-year-old site near Sch?ningen, Germany, wooden spears have been found associated with the remains of 19 horses, suggesting Homo heidelbergensis mounted a carefully planned ambush there. "That early humans had sophisticated cognitive abilities comes as no surprise," she says.
Last week, some of Wilkins's colleagues discovered 71,000-year-old stone tips that may have belonged to the world's earliest arrows. What should we make of the fact that this find, too, was made in South Africa?
It might just reflect the amount of work going on there, given that vast areas of Africa have yet to be explored for prehistoric remains. "Alternatively, it may be that the unique environmental conditions of southern Africa are in part responsible for technological innovation," says Wilkins. Though it is unclear what these conditions may have been.
Journal reference: Science, DOI: 10.1126/science.1227608
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