Scientists have discovered evidence of what may be the world’s oldest known human burial. The team argues that several Homo naledi remains, dating back about 300,000 years, show signs of having been intentionally buried in a chamber deliberately marked with symbols, suggesting complex funerary behavior. But other scientists aren’t so sure.
In 2013 a team of scientists uncovered a remarkable fossil find in a cave system in South Africa – the remains of about 15 individuals who belonged to a completely unknown species of human. Named Homo naledi, the hominin bore a striking combination of modern and archaic features, which made it difficult to place on the evolutionary tree.
Now, the team behind the original discovery have made some bold new claims about the species and site. Depressions in deep chambers in the cave were found to contain the bodies of several Homo naledi adults and young children which appeared to have been intentionally buried after death.
The researchers cite several details that led them to this conclusion. Firstly, the depth of the cave alone suggested deliberate burial. The bodies were found in fetal positions, with one holding a stone tool. And the depressions seemed to have “cut” lines around the edges, suggesting the hole had been excavated artificially and filled back in, rather than a natural depression.
The implications of that are quite profound. For one, it predates the earliest known Homo sapiens burials by more than 100,000 years, and it suggests far more complex behavior than it was thought Homo naledi should be capable of, given its much smaller brain.
“If you are granting them the specialized behavior of burials, it is not something one individual could do,” said Professor Chris Stringer, a human evolution expert at the Natural History Museum in London, who was not involved in the study. “There would have to be a group of them going down there, dragging these bodies with them and then burying them. They would have had to take something down there to dig the holes with. Someone is making fire torches and keeping them alive for the time they are down there. It really is complex and planned behavior. Then you come on to the question of could a creature with no language do this, and that is a whole other can of worms to open.”
Even more striking, the walls of the chamber were marked with carvings that seemed to convey meaning. That included geometric shapes like triangles, squares and cross-hatching, which if made by Homo naledi could have been part of the funerary rituals. Evidence of fire was also present, which of course would be necessary for anyone venturing so deep into the caves.
But the problem is, so far it’s been difficult to accurately date the etchings or fire, so there’s every possibility that they were made by other hominins that ventured into the cave perhaps tens of thousands of years later. Homo naledi’s brain size is also a sticking point for some scientists.
“To have this level of complex behavior with an ape-sized brain is very challenging,” said Stringer. “For me the brain size is a really key issue and problem in all this. Brains are very energetically expensive. The assumption has been that, roughly speaking, the increase in brain size tracks the increase in behavioral complexity, particularly with Neanderthals and us. So, if H. naledi could do all this with a brain half the size, why don’t we? What is all our extra brain power doing if H. naledi is able to do this with an ape-sized brain?”
Other scientists have shown restraint in jumping to conclusions as well.
“This is an admirable attempt to demonstrate that the corpses of at least two individuals were deliberately buried in shallow pits, and one can certainly not rule this out,” the University of Durham’s Paul Pettitt told New Scientist. “I’m not convinced that the team have demonstrated that this was a deliberate burial. Let’s walk before we can run.”
The fact that the paper has yet to be peer reviewed, and the lead researcher is promoting an upcoming book and Netflix special, give reason for a little more pause. Further research will need to be done in the cave system to find more evidence.
The research is available on the pre-print server BioRxiv (PDF).
Sources: National Geographic, Natural History Museum
