THE ANCESTORS of early humans used stone tools to butcher animal carcasses nearly one million years earlier than previously thought.
Archaeologists revised the date after spotting distinctive cut and crush marks made by stone tools on animal bones dating to 3.4 million years ago.
The remains, including a rib from a cow-like creature and a thigh bone from an animal the size of a goat, were recovered from riverbed sediments in Dikika,northern Ethiopia, last January.
The marks show where stone tools were used to slice and scrape meat from the carcasses and where the bones were crushed to expose the marrow inside.
The discovery suggests meat was on the menu far back in our evolutionary history, and long before the arrival of the first human species, Homo habilis, 2.3 million years ago.
“We were just walking along when we discovered the two bones,” said Shannon McPherron, an archaeologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig.
“We picked up the rib fragment, flipped it over and there were these two, clear marks. Soon after, we found the second bone, also with a lot of marks on it.”
Until now, the oldest evidence of stone-tool use was a haul of more than 2,600 stone flakes estimated to be 2.5 million years old that was discovered in another part of Ethiopia in 1997. These tools had been shaped to make sharp cutting edges, but in Dikika, the stones were most likely used as they were found.
The butchered bones were discovered close to where the skeleton of a probable human ancestor, nicknamed Lucy, was found. Lucy belonged to a species called Australopithecus afarensisand lived in the region around 3.4 million years ago. At the time, the region was warm and wet, with patches of grassland and heavily forested areas populated with early forms of giraffes, monkeys, elephants and rhinos.
“Now, when we imagine Lucy walking around the east African landscape looking for food, we can for the first time imagine her with a stone tool in hand looking for meat,” said Dr McPherron.
Detailed analysis of the cut marks on the bones showed they differ substantially from tooth and claw marks. One of the marks was embedded with a small fragment of stone, according to a report in the journal, Nature.
The use of simple stone tools to remove meat and marrow marks a crucial moment in the human story. As the ancestors of early humans turned to meat for sustenance, they were able to grow larger brains which in turn enabled them to make more sophisticated tools.
“These bones may take us to the very beginning of that process,” said Chris Stringer, head of human origins at the Natural History Museum in London. “What we need from these sites now are evidence of the stone tools themselves, so we can see if they were manufactured or were natural.”
Lucy and others of her species probably carried natural stone tools around with them to use when they encountered a dead animal. "It's not a trivial thing to leave the trees behind, wander out on to this open landscape and start removing flesh and marrow from a carcass. Those carcasses were attracting carnivores . . . so they were taking a major risk," said Dr McPherron. – ( Guardianservice)