Homo naledi

I got up all bleary-eyed this morning, and before I got my first sip of coffee, the first thing I saw, blasted across Twitter and all the popular news sites, was the news that a new species of human, Homo naledi has been discovered in South Africa. They have the partial skeletons of 15 different individuals, over 1500 bones, all recovered from a single cave. They’re calling it a new and unique species, and further, they’re claiming that the site is a ritual burial chamber.

Whoa. Brain is whirling. This thing is all over the net, over night. Better drink more coffee.

OK, that’s better.

I’m a little put off by the abrupt and sensationalist appearance in pop news sites, but here’s the science paper. It’s published in eLife, an interesting journal I’ve written about before. It’s peer-reviewed, the lead authors have a respectable reputation, and it looks legit. It’s a real discovery: a cache of bones in a very difficult-to-reach, sheltered site. One of the fascinating bits of the story is that the cave is so inaccessible, reached through such narrow crevices, that all the bones were recovered by a team of women who were small enough to fit.


No matter what, this is an impressive and exciting discovery. A whole small population of individuals, all found in one place? There are years of analysis waiting to be done. Here’s the holotype and the large collection of bones used in the first publication. Homo naledi is a small-brained, bipedal hominin, that’s for sure.


Now for my reservations.

  • The researchers haven’t yet dated the specimens! We don’t even have a guess! That’s how preliminary this publication is. I can sort of understand wanting to get an exciting find like this published as soon as possible, but I have no idea where to place this species in the family tree now. Is it 3 million years old, or 300 thousand?

  • It’s been labeled as a new species, but is it? I’m not an expert on human evolution by any means, but it looks like it fits within the parameters of Homo erectus, and the authors note its close resemblance to H. erectus, but also insist that there are small, unique features to the skull. I’d want to see more input from other experts. It’s always tempting to slap a new species name on a new specimen, but I’d be just as thrilled if this turned out to be a comprehensive assemblage of a H. erectus group.

  • The news stories are all speculating that this is a ritual burial site, suggesting that our ancestors had certain cultural practices long before we expected. We can’t say anything about the timing, because we don’t know how old the site is! But there are some suggestive details. The cave is extremely hard to access (although we don’t know anything about accessibility when the cave was in use), and most interestingly, only H. naledi bones are found in the cave. That suggests it was not simply a rubbish pit, or that animal remains naturally washed into it. Ritual burial seems like a good explanation, except that these people had brains the size of an orange.

Most of the coverage right now seems gushing and uncritical, but I recommend the article in the Guardian, which has a good balance of enthusiasm and skepticism. I think it’s a great day for the science of human evolution, but the full details are going to take much longer and much more work to emerge. I’m looking forward to further reports. The world had better fund more anthropology/paleontology research so I don’t have to be kept waiting!


  1. slithey tove (twas brillig (stevem)) says

    One of the fascinating bits of the story is that the cave is so inaccessible, reached through such narrow crevices, that all the bones were recovered by a team of women who were small enough to fit.

    Through a Feminist Lens, eh?
    odd how these significant fossils are always in the most inconvenient locations… aliens put them there to hide their experiment victims from the rest of mankind…
    bafflegab … garblegarg…
    nothing intelligent to contribute… move along…

  2. says

    I found it interesting that the skeletons found seemed to have no obvious signs of injury/damage. I think one of the papers authors described the individuals as “the healthiest dead people” or something like that.

    If anything the nuggets of the unknown like how they died, the date they lived, why they are in a cave etc just makes this story all the more interesting without having to worry about where the species fits into the homo family as we can hopefully look forward to years of analysis.

    Apparently you can download 3D models of the bones from an opensource website. Anyone fancy 3D printing a homo naledi skull?

    Is anyone on here clued up on how these sort of digs work? As well as the bones would the surrounding area have been investigated like a crime scene would be, so that evidence other than bones is collected?

  3. says

    The biology is neat and all but I’d be really interested in more info about the site itself. What kind of culture or behavior can we extrapolate from, not just the bones, but from the entire tableau of that cave.

  4. Reginald Selkirk says

    They’re calling it a new and unique species

    Right. Wake me when some paleontologist working on human ancestors claims that their most recent find is just more of the same old same old.

  5. Reginald Selkirk says

    The researchers haven’t yet dated the specimens! We don’t even have a guess!

    Just a wild guess, but I think those fossils are from the past, not the future. That cuts the field of possibilities in half.

  6. numerobis says

    That’s how preliminary this publication is

    The article doesn’t read to me as being rushed. It’s not just “15 skeletons in a cave that look a bit funny” — they also have some morphological analysis.

    I find caving pretty scary on its own, when you’re squeezing through passages only a foot wide or high (or less, in this case). Then imagine you come upon a whole bunch of human bones. I’d flip out.

  7. says

    Oh, getting into that chamber…that has screaming claustrophobia written all over it. I’m impressed by the team that got in there and made the recovery.

  8. numerobis says

    At the guardian (link in the OP):

    The conclusion is not widely accepted by others. “Intentional disposal of rotting corpses by fellow pinheads makes a nice headline, but seems like a stretch to me,” said Jungers. Zollikofer agrees. “The ‘new species’ and ‘dump-the-dead’ claims are clearly for the media. None of them is substantiated by the data presented in the publications,” he said.

    Harsh! And they say that computer scientists are hyper-critical.

    [team member] Hawks is open to other explanations, but said that disposal made sense. “The evidence really tends to exclude the idea that they entered the chamber one at a time, alive, over some time, because we have infants, small children, and very old adults who would almost certainly not have managed to get into this chamber without being deposited there.”


    One thing to note: without fire (or more recently electricity, but I doubt they found any Petzl gear on those hominids), you’ll be utterly blind in those caves. Unless there was somehow a light shaft that’s since been sealed off, how were those hominids blindly ambling about those tight squeezes? With flaming torches?

  9. Michael says

    @7 That’s the thing that always put me off of cave exploring. 25cm! If you got stuck, there isn’t much anyone can do to help you.

  10. says

    Michael @ 9:


    Thing is, I could fit that whole traverse. Whether or not anyone would be able to talk me into doing that is a whole ‘nother thing.

  11. says

    We have no idea what the cave was like whenever it was in use — there could have been some relatively easy access, which was closed off by one good rock fall. Or two.

  12. marcoli says

    I too am excited by this find. You anticipated my points very nicely. I suspect that over time the consensus will be that this is H. erectus, and it is known that that species had a range of morphologies formerly assigned to different species. As for ritual burial, that does sound like a reasonable interpretation so far. Alternatively, it could have been a family group that became trapped in the cave and died — or is there sign that they were ‘placed’ in certain spots?

  13. leerudolph says

    Reginald Selkirk @5:

    Just a wild guess, but I think those fossils are from the past, not the future.

    Now you’ve got me wondering…what could constitute physical evidence that a fossil (say) was from the future rather than the past? I don’t offhand see how C14 dating could be coaxed into doing it. Maybe if one found radionuclides, of the specific sorts whose absence from certain human artifacts (e.g., old wine) is accepted as evidence that they predate atmospheric testing of nuclear weapons, in quantities so great that they would most reasonably come from a time after that large-scale nuclear war that we haven’t had YET? But for those to be in a fossil would require too much geological time to have passed after that war…

    This has probably been addressed in speculative fiction, somewhere. Anyone have an idea?

  14. Reginald Selkirk says

    RE #14: Advanced materials is the usual – exotic metal alloys, nanofabricated parts, etc. As for fossils, there might be bogus speculation as to the future of human evolution – small bodies, huge egg-heads. But these would just say “future,” they wouldn’t give actual dates.

  15. Infophile says

    @14: Well, let’s say you find the head of your friendly neighborhood android, who is not now, nor has he ever in the past been, missing a head. Then when you go to investigate it you end up traveling to the past and he loses it head. But thankfully you have the spare you found earlier to replace it with.

    (For those who don’t get the reference, that was an episode of Star Trek: The Next Generation)

  16. numerobis says

    We have no idea what the cave was like whenever it was in use — there could have been some relatively easy access, which was closed off by one good rock fall. Or two.

    Man that would suck: the whole family’s safely in the cave, crunch, now you’re trapped in total darkness. A few hundred thousand years later, a new way in has opened up and you’ve got people speculating that it was a ritual burial.

  17. says

    A quote from Berger

    “You have a cave that has always been in the dark and has never been exposed to the outside world. There’s no water flowing in. No other animal could get into that chamber. And you have a whole bunch of this one species of hominin, that don’t come in at the same time, and that have no damage, or signs of scavenging. Wanna call it burial? If we found them in any human context, anywhere, you would. We have no better hypothesis.”

  18. bojac6 says

    TheDawgLives @16
    If you haven’t read it, the book “The Descent” (which the movie claims it was based on) is very different and a fun read. Basically there is another intelligent hominid on Earth in the modern day, that lives in a world spanning cave system that has only a few access points to the surface (like Journey to the Center of the Earth really). It’s the origin of Underworld Myths and demons and stuff. It’s pretty cool, though I haven’t read it in years and I remember the third part went a bit off the rails with a huge tone shift.

  19. treefrogdundee says

    Even if these turn out to be nothing more than remains of Homo erectus and are dated right in the middle of that species’ known existence, the simple fact that they were located in such a location and manner speaks overwhelmingly of their intentional placement and is thus by itself an amazing bit of new knowledge.

    On a more depressing note, I am still in the midst of a mental hangover and heartbreak on hearing that Rupert Murdoch has scooped up National Geographic. I guess 127 years will be all she wrote…

  20. wcorvi says

    “They’re calling it a new and unique species ….”
    Ah HA! And the creationsts claim there ARE no new species! PROOF!

  21. quotetheunquote says

    This is great stuff – must be very exciting for their (the researchers’) whole academic community. All that material, in one place…

    @theDawglives #16

    I only read a very brief story about it in the Globe & Mail this morning, but I got the impression that they had evidence that the bodies were accumulated there over time (although how long a period, this story did not elaborate on), and there was no evidence that the cave had been lived in. So that points away from the “family group trapped and died” by flood or rockfall hypothesis.


  22. Rich Woods says

    @leerudolph #14:

    Now you’ve got me wondering…what could constitute physical evidence that a fossil (say) was from the future rather than the past?

    It’d be absolutely covered with tachyons. That or it would look like a rabbit might in 600 million years time.

  23. slithey tove (twas brillig (stevem)) says

    @leerudolph #14:

    Now you’ve got me wondering…what could constitute physical evidence that [an object] was from the future […]?

    good question. interesting hypothetical:
    IFF Ttimewarps were possible and something “popped” from the future to the present, what evidence would there be, in the object itself, that it was from the future and not the past nor some great distance?

    A most challenging gendankenexperiment. With Einstein ghost in my pocket, maybe he’ll give me a thought or two. Until then, my only answer is: “Inconceivable”.

  24. Reginald Selkirk says

    Rich Woods #24: It’d be absolutely covered with tachyons.

    So all we have to do is invent a tachyon detector…

  25. Michael says

    @12 PZ I’m well aware that access to the cave was probably a lot easier in the past. I’ve visited a couple of ‘tourist’ caves that were located by cavers through small holes one is barely able to fit through (which were then widened to allow tourists to walk in) and had been much easier to access when the earlier inhabitants had lived in them. I just find the idea of crawling into a small hole, not knowing if it is big enough for me to fit, let alone turn around when I want to leave, an uninviting idea.

  26. tkreacher says

    For anything concerning evidence that something came from the future, one must also account for alien thing-a-ma-stuff. Like tech examples or irradiated what-nots and stuff that looks like evolved future rabbits and the like, I would assume.

  27. numerobis says

    He shone his headlamp down the dark crevice, and couldn’t see where it ended. He knew of at least one other caver who also stared down the crack, and decided it was too dangerous. He began to lower himself, feet-first, into the narrow vertical opening.

    “It’s exciting to find something new,” Tucker, now 27, told The Associated Press on Thursday, trying to explain why he took the risk.

    Tucker, just wiry enough to fit, followed the crack deeper into the earth for nearly 13 yards (12 meters).

    “It’s 18 centimeters (7.1 inches) wide, with these jagged rocks, sticking into you from all sides. And suddenly at the bottom, it opens up into a large chamber with really stunning stalactites hanging from the ceiling,” Tucker said, hunching his shoulders and jutting his elbows out as he re-enacted the descent.


  28. se habla espol says

    “[R]eally stunning stalactites”, hunh. Makes me wonder whether the passages might have been constricted by accretion, over the millenia.

  29. says

    (Looks at diagram of cave again…)


    I don’t think I’m particularly claustrophobic. Or didn’t. But yikes. I’m just trying to imagine what it would feel like, being in one of those crawlways, trying not to think about the mass of rock above. Seriously impressive, the women who went in after those bones.

  30. petemoulton says

    Our esteemed host says: “Is it 3 million years old, or 300 thousand?”

    Now, PZ, you know perfectly well they can’t be any more than about 6000 years old./s

  31. says

    I did some research work in caves many years ago and can imagine the working conditions for the people who were carrying out the excavations. However I feel there must have been an earlier and easier approach to the chamber when the bones got there. From the diagram of the cave, and the dimensions given there would be significant problems in carrying a dead body, presumably showing signs of rigor mortis, particularly if you didn’t have any lights and were operation in the pitch dark.