1.45 million years ago it was a hominin-eat-hominin world

Smithsonian Museum researchers have identified the earliest known evidence that humans’ close evolutionary relatives butchered, and probably ate one another.

Publishing in Scientific Reports paleoanthropologist Dr Briana Pobiner analysed eleven marks on a 1.45 million year old shin bone, or tibia. 

Pobiner was analysing the fossilised shin bone for signs of animal bite marks, and found evidence of human butchery instead.

“The information we have tells us that hominins were likely eating other hominins at least 1.45 million years ago,” Pobiner says.

The species of human ancestor the shin bone belongs to remains unclear. It was originally thought to belong to Australopithecus boisei but then in 1990 it was identified as Homo erectus. 

Independent analysis by co-author Michael Pante from Colorado State University, compared 3D scans of the eleven markings with a database of 898 teeth, butchery and trample marks.

The analysis revealed nine of the marks were consistent with damage inflicted by stone tools. 

While the marks do not prove that the human relative who inflicted them also made a meal out of the leg, Pobiner says this seems to be the most likely scenario. 

All nine marks were oriented the same way and located where a calf muscle would have attached to the bone – a good place to remove flesh.

“These cut marks look very similar to what I’ve seen on animal fossils that were being processed for consumption,” Pobiner says. “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.”

The other two marks on the fossilised tibia were likely bite marks from a big cat, which Pobiner suggests could have come from a saber-tooth cat.

None of the stone-tool cut marks overlap with the two bite marks, making it challenging to infer anything about the order of events that took place. 

For instance, a big cat may have scavenged the remains after hominins removed most of the meat from the leg bone. On the other hand, a big cat could have killed an unlucky hominin and then was chased or scurried away before opportunistic hominins took over the kill.

Pobiner stops short of calling the discovery cannibalism, given the victim and perpetrator could have come from different species of early human relatives.

The fossilised bone comes from the collection of the National Museum of Kenya’s Nairobi National Museum, where Pobiner originally went searching for information about prehistoric predators.

She says the finding demonstrates the value of museum collections.

“You can make some pretty amazing discoveries by going back into museum collections and taking a second look at fossils,”

“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.”