Cannibal relatives: Ancient humans likely butchered each other for food

Researchers believe ancient humans likely butchered each other for food, as cut marks on the recently found 1.45 million years old fossilised bones clearly show handheld stone tools were used to carve the flesh from the shinbone of one of the skeletons.

In the study published Monday in the journal Scientific Reports, researchers analysed nine cut marks on a left shin bone from modern human ancestors found in northern Kenya.

Researchers, from the Smithsonian’s National Museum of Natural History in the US, said the cut marks seem to have been caused due to damage inflicted by stone tools.

"This could be the oldest instance of cannibalism in a human relative species known with a high degree of confidence and specificity," they noted.

A co-author of the study Dr Briana Pobiner said: “The information we have tells us that hominins were likely eating other hominins at least 1.45 million years ago.”

Dr Pobiner said also noted: "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 recognised."

While observing the fossils and their shin bone for bite marks, Dr Pobiner noticed what "looked to her like marks of butchery" and then compared the samples with controlled experiments.

As a result, they identified nine of the 11 marks as clear matches for the type of damage inflicted by stone tools and the other two as likely bite marks from a big cat.

Dr Pobiner said: "The cuts are located on the shin where a calf muscle would have attached to the bone — a good place to cut if the goal is to remove a chunk of flesh."

"These cut marks look very similar to what I've seen on animal fossils that were being processed for consumption. 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," Dr Pobiner said.

However, scientists maintain that there is not enough evidence to conclusively "infer this as a sign of cannibalism as that would require the eater and the eaten to hail from the same species."

Scientists expressed that the use of stone tools also does not narrow down which species might have been doing the cutting.

Some researchers have further called into question the once-common assumption that only one genus, Homo, made and used stone tools.

It is believed that these fossils may be evidence of prehistoric cannibalism, it is also likely that this may have been a case of one human ancestor or relative species chowing down on a cousin species.

It is also hard to infer anything about the order of events that took place based on the bite marks, researchers say.

"A lion may have scavenged the remains after hominins removed most of the meat from the leg bone or alternatively, a big cat that killed an unlucky hominin was likely chased off before opportunistic hominins took over the kill," researchers believed.