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Pobiner’s group did a good job of excluding such factors as causes of nine of the 11 incisions on the hominid leg fossil, Hanon says. But Hanon and colleagues have argued that animal trampling or accidental rubbing of the fossil against jagged rocks before it was excavated could have produced the incisions. Researchers described incisions on a partial upper jaw found at a South African site - with age estimates ranging from 1.5 million to 2.6 million years old - as having resulted from slicing through a muscle to remove the lower jaw. Researchers have thus presumed that the leg bone originally rested in sediment slightly younger than that ash deposit.Ī possible earlier case of a butchered hominid, reported in 2000, also triggered debate. The fossil’s age estimate derives from its position just above a volcanic ash layer dated to between around 1.5 million and 1.6 million years ago. It was found on the surface of a site in northern Kenya after coming loose from eroding sediment. Although Stone Age cannibalism may have occurred, “the present evidence is not strong enough to enable such an inference,” he says.įurther complicating matters, the original context of the leg fossil is unknown. Pobiner’s findings may reflect scenarios such as cannibalism to supplement other food sources, some sort of ritual practice that did not include cannibalism or the consumption of a defeated enemy following a fight between groups, suggests Saladié.Īrchaeologist Yonatan Sahle of the University of Cape Town in South Africa agrees that the interpretation remains up in the air. There is no way to know whether flesh from meatier body parts, such as the shoulder and upper leg, was also removed, he says.īut stone-tool incisions on a partial leg bone do not provide enough evidence to determine whether hunger motivated flesh removal, counters zooarchaeologist Palmira Saladié of the Catalan Institute of Human Paleoecology and Social Evolution in Tarragona, Spain. Cutting into the fleshy part of a lower leg probably reflected a need for food rather than a ritual act of some kind, says Hanon, who was not part of Pobiner’s team. Zooarchaeologist Raphaël Hanon of Wits University in Johannesburg agrees. “We assume the intention of whichever inflicted the cut marks was simply to cut off meat from the bone to eat it, based on hunger,” Pobiner says. Reasons for that act remain hazy, especially with only a single, fragmentary bone in hand.

The incisions on the fossil cluster around a spot where a calf muscle attached to bone, consistent with the removal of a chunk of flesh, Pobiner says. There is also no way to tell whether a hominid from the same species or a different species left stone-tool marks on the leg fossil. habilis or a relatively small-brained species called Paranthropus boisei, Pobiner and colleagues say. No consensus exists on the species identity of the ancient leg fossil. The other two marks resulted from the bite of a big cat, perhaps a saber-toothed cat. Nine marks closely matched stone-tool damage, Pobiner says. Depths of marks are measured in micrometers. Michael Pante Analyses of 3-D models of the deepest marks on a hominid fossil leg bone, including the ones depicted here in blue and green, pegged the incisions as cuts made by another hominid wielding a stone tool.

Analyses of 3-D models of the deepest marks on a hominid fossil leg bone, including the ones depicted here in blue and green, pegged the incisions as cuts made by another hominid wielding a stone tool. The pair created 3-D scans of the bone marks and compared them with 898 bone marks known to have been made by stone cutting tools, stone pounding implements, the teeth of crocodiles, lions and other nonhuman predators, or cows trampling the ground ( SN: 11/6/17). Pobiner sent molds of 11 incisions on the fossil to paleoanthropologists Michael Pante of Colorado State University in Fort Collins and Trevor Keevil of Purdue University in West Lafayette, Ind. But marks on the leg bone looked to her like butchery damage. She wanted to identify which nonhuman predators hunted and ate ancient hominids. Pobiner first examined the incised leg bone while studying fossils held at the Nairobi National Museum in Kenya. But there’s debate about that interpretation.

Those incisions are the oldest convincing example of such butchery and possibly cannibalism among ancient hominids, says paleoanthropologist Briana Pobiner of the Smithsonian Institution in Washington, D.C.