In 2015 palaeoanthropologists discovered what might be the oldest burial ever. A 2 milllion year old human relative carried its dead deep into a cave; disposing of them in a “burial chamber” that could only be reached by crawling through the pitch black.
And if that’s not impressive enough for you: this was all done by a species with a chimp-sized brain called Homo naledi. They seem to have carried out these burials for thousands of years; indicating a long-lasting social structure like those seen in modern humans.
The fact that such a small-brained species performed this “modern” behaviour could rewrite our understanding of the filthy monkey men we evolved from. Unless, of course, they actually didn’t perform any burials.
A review of the evidence for Homo naledi‘s funeral parlour suggests they might not been deliberately burying their dead after all.
The evidence for burial
The main evidence for this ancient burial comes from the fact the initial discoverers ruled out pretty much every other cause. They worked for more than a year after the initial discovery, looking for evidence that something else was responsible. And they just couldn’t find it.
For example, there are other caves full of hominin bones from the time period (some of which can be found nearby). However, these accumulations were the result of “death traps.” These are creatively titled holes in the roof of the cave that animals fall through and die. Yet the Homo naledi burial site shows no evidence of such a hole in the roof. Additionally, death traps don’t tend to discriminate about who falls into them. So you wind up with a mixture of animals, humans, and everything in between. Yet only Homo naledi fossils were found at this burial site.
Another alternative is that a different species dragged the remains into the cave. Some predators will hide their prey away for later consumption. However, none of the examined bones had evidence of tooth marks; suggesting this didn’t happen. In fact, most of the damage done to the remains appears to have happened long after death; like bugs scratching the bones as they ate the rotting flesh.
Yet another explanation is that the remains were washed into the cave. But much like the death trap, this should wash everything into the cave; not just Homo naledi. The researchers also observed that the sediment in the cave doesn’t look like something which would have accumulated as a result of water.
Birds against burials
All of this evidence seems rather impressive. Or rather, the lack of evidence for alternatives is impressive. Except for the fact it seems there’s so little data available for the site that these alternatives can’t actually be ruled out.
For example, evidence against carnivores being responsible includes the fact no bones with teeth marks are found. Yet the surface of only 1% of the fossils is intact. So there could be carnivore marks on 99% of the bones and we’d have no idea. Further, whilst thousands of fossils were recovered from the site each individual Homo naledi found had huge chunks missing. Again, think how much evidence might have been lost there.
So we have two sides, both arguing that their opponents have no evidence against them. But do either have positive evidence for their position? Well, it seems like there is actual evidence for the claim that they weren’t buried in the cave: birds.
The author of the review notes that there is scattering of small mammals remains inside the burial chamber. This pattern is seen in the entrance to other caves, where birds of prey take shelter and consume their prey. Hence the scattering of small mammals. As such, the author concludes, this is a clear sign that the cave was a lot more accessible in the past. It’s unlikely birds of prey could have travelled in the dark through all the twisty turny passages to get to the chamber in its current format.
And just in case you think that interpretation is stretching a bit far; it’s worth noting bird bones were actually found in the cave. There was also evidence of land snails; which typically avoid dark passages. Again, more evidence the chamber wasn’t always so difficult to reach.
If it was more open in the past then the chamber may well have been used by carnivores as shelter whilst they eat their prey. And whilst there isn’t any direct evidence of carnivores, the fact that many of the bones of these fossils are missing (and there are few complete elements) suggests that they might have played a role.
Digging up the truth
I was initially skeptical of the evidence for the burial. After all, they didn’t provide any evidence that it actually happened. Just that it wasn’t the result of these other events. Now I feel justified (and slightly smug) by this latest review.
That said, a large part of both sides’ arguments rests on pointing out the absence of evidence for their opponents. So I’m not sure we can really rule anything out yet. The scattering of evidence (and bird prey) suggests that we will eventually rule out the burial hypothesis; but we haven’t quite got there yet.
Fortunately, there’s a lot more to be information about this cave just waiting to be studied. The tough conditions of working in such a tiny space meant they couldn’t examine everything in there. As such, the initial researchers only scratched the surface. Literally, they didn’t even reach the bedrock of a single chamber of the cave.
Hopefully somewhere in there is the final piece of evidence that shows whether or not Homo naledi really buried their dead. And hopefully it shows that they didn’t, so I can continue being smug.
The evidence so far seems to be leaning that way, so I’m not going to stop feeling smug any time soon.
Did ancient hominins carry out a burial? The lack of evidence for alternatives led many to conclude yes; but that evidence isn’t as clear cut as they think.
Dirks, P. H., Berger, L. R., Roberts, E. M., Kramers, J. D., Hawks, J., Randolph-Quinney, P. S., … & Tucker, S. (2015). Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa. eLife, 4, e09561.
Val, A., 2016. Deliberate body disposal by hominins in the Dinaledi Chamber, Cradle of Humankind, South Africa?. Journal of Human Evolution.