Signs of cannibalism: Fossil reveals human ancestors slaughtered one another for reasons other than rituals

Nine cut marks found on a fossilized shin bone suggest that ancient human relatives killed and maybe ate one another 1.45 million years ago, according to a new study. Briana Pobiner, a paleoanthropologist at the National Museum of Natural History in Washington DC, discovered the fossilized tibia in the collection of the National Museums of Kenya’s Nairobi National Museum. Pobiner was looking through the collection for bite marks from extinct creatures that may have preyed on early hominins when she came across incisions that appeared to have been produced with stone tools. “These cut marks look very similar to what I’ve seen on animal fossils that were being processed for consumption,” Pobiner said in a news release. “It seems most likely that the meat from this leg was eaten and that it was eaten for nutrition as opposed to for a ritual.”

What the cut marks show

Michael Pante, a paleoanthropologist at Colorado State University and study coauthor, constructed 3D models based on molds of bone markings. He compared the shape of the cuts with an existing database of 898 individual teeth, butchery, and trample marks created during controlled experiments. Pobiner hadn’t told him she felt the cut marks were made by stone tools, but his investigation led him to the same conclusion.

Because the cut marks are all oriented in the same direction, a hand holding a stone tool might have made the marks one after the other without changing grip. Because a leg bone doesn’t provide as much taxonomic information as a cranium or jawbone, it’s unclear which species of ancient hominid the shin bone belongs to. The preserved tibia was first recognized as Australopithecus boisei, then as Homo erectus in 1990. The advent of complex stone tools is linked to the emergence of the Homo genus, which includes our species, Homo sapiens, but recent evidence suggests that other ancient hominins may have used stone tools even earlier.

Hominins consuming hominins

The incisions do not establish conclusively that the ancient human relative who caused the harm also ate the limb, but Pobiner believes it is possible. The marks are where a calf muscle would have been linked to the bone, which would have been an ideal area to cut if the goal was to remove the flesh. “The information we have tells us that hominins were likely eating other hominins at least 1.45 million years ago,” Pobiner said. “There are numerous other examples of species from the human evolutionary tree consuming each other for nutrition, but this fossil suggests that our species’ relatives were eating each other to survive further into the past than we recognized.”

In the past, cannibalism was more common

Cannibalism may have been more common in the past than previously thought, according to Silvia Bello, a researcher in human origins at London’s Natural History Museum, who noted that evidence for the behavior had also been found at archaeological sites associated with Neanderthals and early modern humans.

Cannibalism, for example, was practiced by Neanderthals 100,000 years ago in what is now France, maybe due to a warmer climate making food harder to come by. The latest study, published Monday in the journal Scientific Reports, is “significant because this new find suggests that cannibalism might have been practiced, at least occasionally, a long way back in our ancestral history,” said Bello, who was not involved in the research.

Her colleague Chris Stringer, research leader in human origins at the Natural History Museum in London, believes the shin bone is not the oldest documented evidence of human relatives murdering one another. He stated that cut marks were discovered on the cheekbone of a 2 million-year-old hominid fossil discovered in Sterkfontein, South Africa, in 2000. However, Pobiner stated that the origins of the cut marks, in that case, were questioned. “This new evidence looks quite convincing and adds to the evidence for cannibalism very early, as well as the considerable evidence from later, humans,” said Stringer.