A Curious Look At The 3.39 Million Year Old “Stone Tool Markings” From Dikika, Ethiopia

I don’t know who this is worse for, the editors & reviewers over at Nature or the authors of the article who can’t tell the difference between crocodile teeth markings and stone tool modification, nor raise the possibility. The paper, “Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia,” very confidently proclaims unambiguous evidence for,

“stone-tool-inflicted marks on bones found during recent survey work in Dikika, Ethiopia, a research area close to Gona and Bouri. On the basis of low-power microscopic and environmental scanning electron microscope observations, these bones show unambiguous stone-tool cut marks for flesh removal and percussion marks for marrow access.”

Butchered by early humans or eaten by crocodiles? Image: David DeGusta

Given that the said rib fragment, DIK-55-2, came from a prehistoric lacustrine site. These markings could have been produced by crocodiles. Crocs, if you aren’t aware of (ahem editors and publishing group) are very abundant in the Rift Valley — both currently and prehistorically. On top of that, crocs like to eat meat and scavenge. Yes its true, they are carnivores. Australopithecines were at most ominivores, with wide based teeth useful in grinding tubers and nuts. Crocs have more meat shearing, bone crushing teeth than 3.39 million year old stone tools, which there are none of at the moment.

Given that there really isn’t an archaeological record for Australopithecine tools, I’ll take a gander and say crocs like to eat meat and scavenge more effectively than A. afarensis could make and use said tools to butcher a large ungulate. They have been on this Earth for roughly 197 million years more than hominins have and they are really good at what they do… Again, probably better than a species of hominins who did not live in the Stone Age. It is just as likely (if not more) that the markings were produced by crocodiles just given the ecological context.

Now just how different at cut marks from crocodile teeth marks? David DeGusta, from Stanford University, compared and contrasted the two different markings using images from Njau and Blumenchine (2006) paper titled, “A diagnosis of crocodile feeding traces on larger mammal bone, with fossil examples from the Plio-Pleistocene Olduvai Basin, Tanzania,” to those published in the current Nature article. I’ve inserted DeGusta’s image into this post on right for your own inspection. DeGusta was also on Science Friday, discussing this possibility, with one of the article’s authors, Zeresenay Alemseged. What do you think? Do they look completely different or similar? Seriously, I am asking you to comment. I’d like to know what you see.

Personally I don’t see much of a difference. I agree that stone tools marks are more V shaped, while croc teeth are more pitted/rounded. But take this into light: tool use, especially butchery, is a very human behavioral trait. In their search to attribute this human behavior to a primitive hominin species who roamed 800,000 years earlier, to the era of Australopithecus afarensis, without considering another possible explanation, the authors and editors of Nature were somewhat foolish.

Many paleoanthropologists are in this mad rush to claim their precious find is the most human of hominins, so as to etch their name into the textbooks in rewriting human evolution, that they sometimes forget about doing thorough comparative science. And many publications are in this mad rush to publish the most human of findings, that they sometimes forget about thoroughly editing scientific works. Think that could be the case? I sure do… Why should we settle on secondary evidence for Australopithecine stone tools when none have been found yet, and when another possibility hasn’t been extensively exhausted?

    McPherron, S., Alemseged, Z., Marean, C., Wynn, J., Reed, D., Geraads, D., Bobe, R., & Béarat, H. (2010). Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia Nature, 466 (7308), 857-860 DOI: 10.1038/nature09248

24 thoughts on “A Curious Look At The 3.39 Million Year Old “Stone Tool Markings” From Dikika, Ethiopia

  1. Honestly, they look pretty dissimilar to me.

    I assume that DeGusta chose images with similar magnification, but there’s no indication of scale in the montage that you’ve provided, and I’d like to see it before I make up my mind. But I do agree that it’s a worthwhile question to ask whether these marks could have a more prosaic explanation.

  2. Thanks for posting this. I think, given the fact that it’s another 700,000 or so years before we find any other evidence of stone tools or cut marks, and then they are everywhere, it’s best to remain skeptical about these marks. Based on the pictures they seem to be ambiguous at best.

  3. I’m sorry, Kambiz but your links point to “nowhere”. Sure, there’s a mention of Almesged and De Gusta discussing the matter but seems to refer to some other (unliked) space (maybe a radio program?) The link at the bottom that reads “más en español” (more in Spanish) again links to a short article that only supports the hominin attribution of the cutmarks.

    So the only thing left is the image taken from Niau and Blumenschine’s paper. As you admit the marks of both examples are different. In fact the more I look at them, the more different they appear:

    left: narrow shallow cuts – right: thick deep cuts
    left: very regular shapes – right: most irregular shapes, probably caused by crocs’ peculiar way of butchering meat
    left: no radiation marks – right: many radiation marks around the main marks, again surely caused by croc’s violent way of eating, shaking the corpse a lot
    left: very curious precise V and X double cut patterns (possibly the best evidence of skilled tool use) – right nothing of that

    So what that graph tells me is that the marks of the left were probably NOT the work of any crocodile and there’s at least reasonable possibility that they were made by humans or a similar animal, using tools and skilled intent. The V patterns are very telling, IMO.

    1. They don’t look like croc tooth marks to me. Some colleagues and I did some feeding experiments at the Australia Zoo and we also looked at a bunch of forensic cases to compare to tooth marks we saw in a megafauna site the QM palaeontologist and I are excavating. I was also interested in the OH 7 marks and we thought the croc assessment of this individual by Solomon and Davidson was good (followed up by Jackson Njau). Would be good to see more images or even the actual specimens but from the images I would not go too hard chasing crocs!

  4. One of the popular press articles I’ve read about this mentioned microscopic stone fragments being found in the cut marks. If this isn’t erroneous, wouldn’t it be pretty much of a clincher?

  5. The find is interesting and it has merits. It is a normal part of research that any interpretation will be questioned and tested by peers and over time hopefully a consensus will arrive. Problem is taht in this time and age the need for media coverage and the need of the media to have “results” means that what should be a process of debate is turned into a battle of truths almost immediately.

    I am a strong proponent for popular publication, but this case as well as for instance the Darwinius debacle and the Hobbit debate shows how potentially damaging to open research it can be. Researchers become wedded to their theories, with a strong sense of losing face in public if they are proven wrong and this is actually worrying. Is Nature and Science turning into the worst enemies of good research?

    1. Great comment, ArchAsa.

      I believe that so long as Science & Nature remain the ‘top’ and a determinant of future grant funding, this problem will only worsen. I really don’t see a way out of it, until researchers publish in less popular journals that review with more diligence. But then the only reward left to a researcher will be the one of doing good science, and unfortunately doing good science simply doesn’t feed the kids anymore.

      Kambiz

  6. The sets of marks look different to me. It is interesting to compare these marks with the marks made on the 75,000 stone from the Blombos Cave in southern Africa. Those markings are organized in a geometric pattern whereas these marks are utilitarian. Still, the marks on both the Blombos stone and the bones suggest reasoning and deliberate controlled motion. Crocodile victims thrash about until they are dragged under the water. The deeper more rounded marks left by crocodile teeth suggest a more violent motion.

    If true, this find pushes back the use of butchering flints in the same region from 2.6 to 3.4 million years ago. That doesn’t surprise me since there always seem to be material antecedents in this business, and a wider diffusion than generally recognized.

    “Several hundred double-edged cutting implements discovered at nine sites in southwestern Crete date to at least 130,000 years ago and probably much earlier, Strasser reported January 7 at the annual meeting of the American Institute of Archaeology. Many of these finds closely resemble hand axes fashioned in Africa about 800,000 years ago by H. erectus, he says. It was around that time that H. erectus spread from Africa to parts of Asia and Europe.” From here:
    http://news.discovery.com/archaeology/ancient-hominids-sailors-seas.html

  7. One of the popular press articles I’ve read about this mentioned microscopic stone fragments being found in the cut marks. If this isn’t erroneous, wouldn’t it be pretty much of a clincher?

    This is mentioned on page 11 of the supplemental material.

  8. Guess you didn’t like my earlier comment, which you’re sitting on for some reason.

    Let’s try again:
    Your comment is pretty self-righteous. Dr. C. Marean of ASU lends credibility to this study, lots of credibility. Greg Laden (on his blog), who’s looked at cut marks in the fossil record, thinks they’re cut marks too. The marks really aren’t all that similar, per comments made by others above and by your own admission.

    DeGusta, a former student of Tim White, is echoing comments made to the press by Tim. David was pretty rude on NPR imo; getting canned at Stanford apparently hasn’t increased his self-awareness.

    This doesn’t prove anything about hunting per se, even if it turns out to be true and replicated by others. Meat consumption need not imply hunting skills. Scavenging happens. However, chimps hunt; chimps use tools. Why should anyone be shocked that australopiths might have also done both once in a while?

    1. Hey, when/where did I write that the tools had to be used to hunt?

      Also, let’s get some things straightened out because you clearly skirted the topic to support your argument. Chimps use tools but not stone ones specifically to hunt. They use stone tools to crack open nuts. They use sticks and twigs to fish for ants and termites. The most a chimp has been seen to use a tool to hunt is a stick. And chimpanzees have not been observed to butcher a kill or meat with any sort of tool, not wooden nor stone.

      Last I checked, stone tool ≠ wooden tool. They are very different both in creation and usage.

      Now, its clear you are in the pro-australopithecine stone tools fan club and are prone to bias your comment and rebuttal to the likes. So you avoiding to acknowledge the difference between chimpanzee tool usage and hominin tool usage is somewhat expected. In my post, I raise the likelihood that modifications to a 3.39 million year old rib can be done by croccodiles, especially since the archaeological record for australopithecines is nill. The authors didn’t even acknowledge this as a possibility which to me shows incomplete analysis and thus faulty science. The fact that Nature continued publishing this, further supports the promoting faulty science.

      I don’t know if you missed that point. It is likely you did. You seem to be reading between the lines, especially since you think I thought there had to be hunting involved. No worries though, I hope you can acknowledge at the minimum that a stone tool is not wooden tool. I think a 3 year old can figure that out.

      Kambiz

      1. Take a deep breath. I urge you to read the extensive supplementary online info that accompanies the Nature paper. The authors evaluated alternatives to cutmarks and cite the Olduvai croc paper specifically. See Marean’s comments on the Nature blog that speak to this issue. Read Laden’s comments on his blog. What do you make of the stone fragments in one of the grooves? Coincidence?

        Stone doesn’t equal wood. Happy now?

        The possibility exists that the putative stone tool that made the marks wasn’t even manufactured by the australopiths, but was merely picked up off the surface and used to deflesh a carcass and crack open the bones for the yummy marrow. I did not attribute the hunting inference to you — but others have made this rather large leap in logic. A couple of banged up bones does not imply a sophisticated hunting strategy, but a generous person might acknowledge that if chimps can hunt in groups upon occasion, then *maybe* early hominins did too. Scavenging is another possibility that completely eliminates the need to attribute premeditated hunting. The only thing I directed at you specifically was this — despite your advocacy for the croc claims, the argument is weak, even by your own criteria, and other experts disagree with the croc attribution. Again, read the SOM. As John Hawks has lamented on his blog, it’s a pity so much important info gets shoved into SOM, but it’s your responsibility to consult it before arm-waving.

        I’m trying to take your blog seriously, and I’m trying to contribute nongratuitous observations that may conflict with your own biases. But you have a childish tendency to lash out when your inferences are challenged, and that seriously undermines your credibilty as an objective blogger.

  9. Well said occamseraser,
    It’s fairly clear from that image that those marks have different morphology. The important thing to remember is that diagnosing toothmarks correctly requires magnification, incident lighting, etc. and creating an image like DeGusta’s only serves to muddy the water for the public. Ill-informed bloggers like Kambiz (sorry to say) perpetuate that problem further. If anyone doubts the ability of Marean and colleagues to identify cutmarks vs. toothmarks I invite them to read Blumenschine et al. 1996 – “Blind Tests of Inter-analyst Correspondence and Accuracy in the Identification of Cut Marks, Percussion Marks, and Carnivore Tooth Marks on Bone Surfaces”. Where are DeGusta and Tim White’s blind tests?

  10. ok so both tools were or atleast not used ,,,so what if and I say this lightly if both were used and shared ?? Two different species or linage ,,sorry had to think of another theorey.
    There are documented cases of shareing in this day and age . So what if ?? What if two diff groups of ..came together at once?? I know I’m jus a layman when it comes to this stuff but hey its fun and great for me cause I hate politics.
    Cheers James

  11. After such certainty in the tone of this article, I was surprised to see two very different kinds of marks in the pics.

    Although I’m a layman, I always seem to be dissappointed in how early primates are portrayed. We know some use tools to this very day. For that matter, so do certain birds.

    So it’s not hard to imagine sophisticated behavior from animals with larger brains. And yet even Neanderthals don’t get much credit. We know they made fine tools and painted impressively in caves and their brains were as large as ours, but if you watch programs on Nat Geo or the Science Channel, apparently they couldn’t cut their hair or bath or stitch clothing or speak.

  12. good point, (the crocs) disagree though. 2 remarks, initial dating put australopitheci remains and also olduwai tools older, a truth in between would make this find less controversial. (and i personally tend to date things on the longer estimates)
    next allthough i dont see much on the pictures of the distortions, the scratches sure seem manmade, toolmade. flint can have a 1 molecule thin edge and is one of the sharpest materials in nature for that. as a result it will before erosion leave marks exactly like that, a sharp cutout with the sharpest expression often slightly at one side of the whole. a sharp and slightly asymetric v cutout. like this.

  13. Take a deep breath. I urge you to read the extensive supplementary online info that accompanies the Nature paper. The authors evaluated alternatives to cutmarks and cite the Olduvai croc paper specifically. See Marean’s comments on the Nature blog that speak to this issue. Read Laden’s comments on his blog. What do you make of the stone fragments in one of the grooves? Coincidence? Stone doesn’t equal wood. Happy now? The possibility exists that the putative stone tool that made the marks wasn’t even manufactured by the australopiths, but was merely picked up off the surface and used to deflesh a carcass and crack open the bones for the yummy marrow. I did not attribute the hunting inference to you — but others have made this rather large leap in logic. A couple of banged up bones does not imply a sophisticated hunting strategy, but a generous person might acknowledge that if chimps can hunt in groups upon occasion, then *maybe* early hominins did too. Scavenging is another possibility that completely eliminates the need to attribute premeditated hunting. The only thing I directed at you specifically was this — despite your advocacy for the croc claims, the argument is weak, even by your own criteria, and other experts disagree with the croc attribution. Again, read the SOM. As John Hawks has lamented on his blog, it’s a pity so much important info gets shoved into SOM, but it’s your responsibility to consult it before arm-waving. I’m trying to take your blog seriously, and I’m trying to contribute nongratuitous observations that may conflict with your own biases. But you have a childish tendency to lash out when your inferences are challenged, and that seriously undermines your credibilty as an objective blogger.

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