Fossils have told about the cannibalism of human ancestors

Fossils studied by paleontologists show that human ancestors killed each other for very unpleasant reasons. Nine cuts on a fossilized tibia suggest ancient human relatives butchered and possibly ate each other 1.45 million years ago, according to a new study.

The fossilized tibia was found in the collection of the National Museums of Kenya at the National Museum of Nairobi by Briana Pobiner, a paleoanthropologist at the National Museum of Natural History in Washington, DC, CNN reports.

Pobiner was browsing the collection looking for bite marks from extinct animals that may have preyed on ancient hominins when she came across marks that looked like they were made with stone tools.

“These tracks look very similar to what I have seen on animal fossils that have been processed for human consumption,” Pobiner said in a press release. “It is most likely that the meat from this leg was eaten and that it was used for food and not for ritual.”

Study co-author Michael Pante, a paleoanthropologist at Colorado State University, created 3D models based on casts of footprints on the bone. He compared the shape of the marks with an existing database of 898 individual teething, butchering and trampling marks created in controlled experiments.

Pobiner didn’t tell him she thought the marks were made by stone tools, but his analysis came to the same conclusion, CNN notes.

All traces are oriented in the same direction, which makes it possible to apply these marks with a hand working with a stone tool, one after another, without changing the grip.

It is not clear to which species of ancient hominins the tibia belonged, because the leg bone does not provide as much taxonomic information as the skull or jawbone. The fossilized tibia was initially identified as Boisei Australopithecus and later, in 1990, as Homo erectus.

The emergence of complex stone tools is associated with the emergence of the genus Homo, which includes our own species, Homo sapiens, but more recent research has shown that other ancient hominins may have used stone tools even earlier.

The footprints alone do not conclusively prove that the ancient human relative who caused this damage also cooked the leg dish, but Pobiner thinks it is possible. The marks are located where the calf muscle would attach to the bone—a good place to cut if the goal was to remove the pulp.

“The information we have tells us that hominins probably ate other hominins at least 1.45 million years ago,” says Pobiner. “There are many other examples of species from the human evolutionary tree consuming each other for food, but this fossil suggests that relatives of our species ate each other to survive, in a more distant past than we thought.”

Sylvia Bello, a human origins researcher at London’s Natural History Museum, said that cannibalism may have been more common in the past than previously thought, noting that evidence for this behavior has also been found in archaeological sites associated with Neanderthals and early modern humans.

For example, the Neanderthals, who lived 100,000 years ago in what is now France, practiced cannibalism, perhaps because the warmer climate made it harder to find food.

The latest study, published Monday in Scientific Reports, “is important because this new finding suggests that cannibalism may have been practiced, at least sporadically, long ago in our ancestors’ history,” said Bello, who took part in the study.

Her colleague Chris Stringer, head of human origins research at London’s Natural History Museum, says the tibia is probably not the oldest known example of human relatives killing each other. He said that marks were reported on the zygomatic bone of a hominin fossil found in Sterkfontein, South Africa, in 2000, which may be about 2 million years old. Pobiner, however, said the source of the cuts in this case was debatable.

“This new evidence looks pretty compelling and adds to the evidence for very early cannibalism as well as significant evidence from more recent humans,” Stringer emphasizes.