Stone tools give early glimpse of human behaviour
KENYA: Traces of the technological revolution that heralded the emergence of modern humans have been discovered near a defunct volcano in Kenya.
The findings include signs of painting, projectile weapons and long-distance trading and show that complex cognitive abilities blossomed 320,000 years ago. That is at least 20,000 years before the oldest known skeletons of Homo sapiens appear in Morocco, deepening the mystery of how and when our species came into existence.
Researchers say our ancestors may have acquired skills that gave them an advantage over other human species, such as Neanderthals and Homo erectus, far earlier than was thought.
‘‘This change to a sophisticated set of behaviours ... may have been the leading edge that distinguished our lineage from other humans,’’ Rick Potts, director of human origins at the Smithsonian museum in Washington DC, said.
Three papers published in the journal Science indicate that the landscape around the Olorgesailie basin in southern Kenya had begun to dry up and large mammals, such as a 4.2-metre elephant and a giant zebra, had started to die out. This seems to have forced the human inhabitants to smarten up in search of new sources of food, ushering in the Middle Stone Age.
They made smaller, specialised stone blades to use as scraping tools or as tips on spears. They sourced obsidian, a black volcanic rock, from other groups up to 65 kilometres away, and hunted smaller prey, such as foxes, hares and rats. They also ground up manganese oxide and bright red ochre to make paint.
Mark Maslin, professor of geography at University College London, said it was now clear that the shift to a harsher landscape had pushed ancient humans to adapt or die. The finds leave important questions unanswered, though. One is whether the artefacts are the handiwork of early Homo sapiens, or of another kind of human that went through a sort of cultural growth spurt before dying out.