Humans’ evolutionary relatives slaughtered each other 1.45 million years ago

Researchers from the Smithsonian Institution’s National Museum of Natural History have identified the oldest conclusive evidence for this Close evolutionary relatives of humans Slaughter and eating most likely.

In a new study published June 26, in the Scientific reportsNational Museum of Natural History paleoanthropologist Briana Pobiner and colleagues describe nine cut marks on a 1.45-million-year-old left tibia from a relative of Homo sapiens found in northern Kenya. Analysis of 3D models of the fossil’s surface revealed that the cut marks were a dead ring of the damage they caused Stone tools. This is the oldest known example of this behavior with a high degree of confidence and privacy.

“The information we have tells us that hominins were likely eating other hominins at least 1.45 million years ago,” Buebner said. “There are many other examples of species from the human evolutionary tree consuming each other for nutrition, but this fossil indicates that relatives of our species ate each other to survive farther back than we knew.”

Bubiner first encountered the fossilized tibia, or shin bone, in the national museum collections of Kenya’s Nairobi National Museum while searching for clues about prehistoric predators that may have hunted and eaten ancient human relatives. Using a hand-held magnifying glass, Buebner dug into her tibia for bite marks from the extinct beasts when instead she noticed what immediately seemed to her like evidence of carnage.

To find out if what she was seeing on the surface of this fossil were indeed cut marks, Buebner sent casts of the cuts — made from the same materials dentists use to make impressions of teeth — to co-author Michael Banty of Colorado State University. She didn’t provide Bunty with any details about what was being sent, and simply asked him to analyze the markings on the molds and tell her what made them. Pante generated 3D scans of the casts and compared the shape of the marks to a database of 898 individual dental, butcher and stomp marks generated through controlled experiments.

The analysis positively identified nine of the eleven signs as clear matches for the type of damage caused by stone tools. The other two marks are likely bite marks from a large cat, with the lion being the closest. According to Buebner, the bite marks could have come from one of three different species of saber-toothed cats that roamed the landscape at the time the owner of the tibia was alive.

By themselves, the cut marks don’t prove that the human relative who struck it also made a meal out of its leg, but Bubener said that’s the most likely scenario. She explained that the cut marks are located where the calf muscle would attach to the bone—a good place to cut if the goal is to remove a piece of meat. All cut marks are also oriented the same way, so that a hand wielding a stone tool can make them all in succession without changing grip or adjusting angle of attack.

“These cut marks look very similar to what I’ve seen in animal fossils that were being processed for consumption,” Buebner said. “It seems likely that the flesh of this leg was eaten for nourishment rather than as a ritual ingestion.”

While this case might look like cannibalism to a casual observer, Bubener said there isn’t enough evidence to make this decision because cannibalism requires that the cannibal and the eater be of the same species.

The fossil tibia was initially identified as Australopithecus boise Then in 1990 as erect manToday, however, experts agree that there is not enough information to assign the sample to a specific type of hominin. The use of stone tools also does not narrow down the species that might have been doing the cutting. Recent research by Rick Potts, chief of the Peter Buck Museum of Human Origins at the National Museum of Natural History, calls further into question the popular assumption that only one species, to turn downStone tools made and used.

So, this fossil could be a trace of prehistoric cannibalism, but it could also be a case of one species stalking its evolutionary cousin.

None of the stone tool cut marks overlap with the two bite marks, making it difficult to infer anything about the order of events that occurred. For example, a large cat may have gnawed the remains after hominins removed most of the flesh from the shin bone. It is also possible that an unlucky hominin was killed by a large cat and then chased or driven away before opportunistic hominins took over the killing.

Another fossil – a skull first discovered in South Africa in 1976 – sparked an earlier debate about the earliest known case of human relatives butchering each other. Estimates of the age of this skull range from 1.5 to 2.6 million years.

Aside from its uncertain age, two studies that have examined the fossil ( Firstly Published in 2000 and last in 2018) they disagree about the origin of the markings under the skull’s right cheekbone. One claims that the marks were caused by stone tools used by our hominin relatives, while the other asserts that they were formed by contact with sharp-edged stone blocks found lying on the skull. Furthermore, even if ancient hominins produced the markings, it is not clear if they butchered each other for food, given the lack of large muscle groups in the skull.

To resolve the issue of whether the tibia fossil that she and her colleagues studied is indeed the oldest hominin fossil that has been cut, Bubener said she would like to re-examine the skull from South Africa, which purported to have cut marks using the same techniques observed in the current study.

She also said this shocking new discovery is evidence of the value of the museum’s collections.

“You can make some amazing discoveries by going back into museum collections and taking a second look at fossils,” Buebner said. “Not everyone sees everything the first time. It takes a community of scientists coming up with different questions and techniques to keep expanding our knowledge of the world.”