Looking for evidence of bite marks that hinted at prehistoric predators hunting our ancient relatives, one researcher has instead found clues to the oldest record of butchering and potential cannibalism instead.
The Smithsonian’s National Museum of Natural History paleoanthropologist Briana Pobiner and team have described nine cut marks on a 1.45-million-year-old shin bone that hails from a Homo sapiens relative, found in northern Kenya in 1970. The exact species of hominin has been debated since its discovery.
Observing 3D models made of the fossil, the researchers noted that the cut marks are not consistent with bites from another animal, but instead indicate the use of a stone tool, most likely employed to remove the flesh attached to the tibia bone.
“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.”
After molds of the cut sites were made, they were turned into 3D scans, which were then compared to 898 other examples of bone damage from trampling, teeth and butchery. Nine of 11 marks on this section of bone were deemed matches for stone tool damage.
The other two marks, according to Pobiner, were likely from one of three types of saber-tooth cats around at the time. Because the cuts and the bite marks don’t overlap, scientists don’t know if the cat caused the demise of the owner of this shin bone or was simply on a clean-up mission later.
Interestingly, while it can’t be determined if a close relative, or even the same species, both inflicted the stone damage and then ate the meat, there are hints of precision that makes a case for ancient hominin meal prep.
The cut marks are located where a calf muscle would have been attached, suggesting that whoever was wielding the tool, knew what they were doing.
“These cut marks look very similar to what I’ve seen on animal fossils that were being processed for consumption,” Pobiner said. “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.”
As for the species, the fossil was initially identified as Australopoithecus boisei, then Homo erectus in 1990. Now, researchers have no idea. And the tool use also doesn’t narrow it down.
However, one thing that is certain is the value of existing fossil collections. This tibia in question is housed in the Nairobi National Museum.
“You can make some pretty amazing discoveries by going back into museum collections and taking a second look at fossils,” Pobiner said. “Not everyone sees everything the first time around. It takes a community of scientists coming in with different questions and techniques to keep expanding our knowledge of the world.”
The research was published in the journal Scientific Reports.