First use of tools pushed back a million years – study

The two mammal bones found in Ethiopia’s Afar region with chips missing and which are about 3.4 million years old could only have been removed by sharp-edged tools according to researchers. Photo: Nature/Dikika Research Project/AFP
Human ancestors were using stone tools to carve meat from the bone of wild animals nearly a million years earlier than thought, according to a new study.
Two mammal bones found in Ethiopia’s Afar region with chips missing that could only have been removed by sharp-edged tools are about 3.4 million years old, said the study, published in Nature.
Cut marks show that implements were used to slice flesh, while hammer-like marks suggest blows used to crack open the bone to get at nutritious – and perhaps tasty – marrow.
Up to now, the oldest known evidence of butchering with stone implements was dated to about 2.5 million years ago.
The crafting and sophisticated use of tools is a watershed moment in human evolution and is often said to set us apart from other animals.
“This discovery dramatically shifts the known time frame of a game-changing behaviour for our ancestors,” lead researcher Zeresenay Alemseged of the California Academy of Sciences said in a statement.
“These developments had a huge impact on the story of humanity.”
The fossil bones – both from mammals, one the size of a cow and the other a goat – were unearthed only 200 metres from the site where, in 2000, the same team of paleontologists dug up the remains of the most complete skeleton of a distant human ancestor ever found.
Like the famous “Lucy” discovered in 1974 in Ethiopia’s Awash Valley, “Selam” – who lived some 3.3 million years ago – was an Australopithecus afarensis, an extinct species between ancient monkey and modern man.
“In light of these new findings, it is very likely that Selam carried stone flakes and helped members of her family as they butchered animal remains,” Dr Alemeseged said.
With stone tools in hand to quickly pull off flesh and break open bones, animal carcasses would have become a more attractive source of food, the researchers speculate.
“This type of behaviour sent us down a path that later would lead to two of the defining features of our species: “carnivory” – or meat eating – “and tool manufacture and use,” said co-author Shannon McPherron, a scientist at the Max Planck Institute for Evolutionary Anthropology in Germany.
“Now, we can for the first time imagine Lucy with a stone tool in hand looking for meat.”
The age of the two bones, one a rib and the other a femur, was determined by examining the volcanic deposits in which there were encased.
Electron imaging analysis and x-ray spectrometry showed the tool-inflicted marks were created before the bones fossilised and could not therefore have been added recently.
Moreover, the marks were clearly left by a sharp-edged tool, and not the teeth of a animal.
It is still not possible to know whether the two-legged hominins who wielded these primitive tools crafted them by chipping at their edges, or whether they simply foraged for naturally sharp rocks.
Noting the lack of large stone at the site, Dr McPherron said they were probably carried from elsewhere.
“One of our goals is to go back and see if we can find these locations, and look for evidence that at this early date they were actually making, not just using, stone tools,” he said.
The researchers also suggested that using sharp stones to slice meat from animal carcasses might have forced our early ancestors to learn teamwork to fend off attacks from dangerous carnivores homing in on the same meal ticket.

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