A paper just out in Nature by McPherron et al suggests that a set of marks found on two bones recovered from the surface very near a locality for which an estimated date can be obtained were caused in antiquity by stone tools wielded by hominids. The date predates any prior known chipped stone tool artifacts of the kind that would leave such marks. The absence of chipped stone tools in the archaeological record in which a claim of a cut marked bone seems unlikely, but it may not be. Earlier research done by Brooks and your truly, and reported mainly as conference papers (e.g. here) and summarized in Panger et all 2002, suggests that prior to drying conditions beginning between 2.5 and 3.0 million years ago the stone tool record would be highly diffuse and almost impossible to find archaeologically.
On the other and, stone tool marks, according to some of key taphonomists and archaeologists are almost always ambiguous, or at least difficult to identify positively (see Tappen and Harris 1995 and Dominguez-Rodrigo et al 2005). A stone tool is a rock. It can scratch a bone. There are other rocks. They can scratch bones too. Telling the difference between a rock scratching a bone and a rock scratching a bone is inherently difficult. One way to do this is to look at a zillion cut marks with stone tools and characterize them metrically and qualitatively (done) and look at a bunch of trample marks where bones are ground and stomped into stony or pebbly ground and characterize those marks (done, but not as much because it is less fun) and see if you can get none overlapping sets of characteristics.
You don't get non-overlapping characteristics, but you do get different looking patterns. So, you can then look at unknown marks and see what pattern they fit. One aspect of the pattern, by the way, is where on the bone the mark is; Some anatomical locations make more sense than others for butchery. On the other hand, one of the reasons we want to look at marks on bones is to find out how the animals were butchered. The tautology meter tends to go off about now.
I've seen a lot of cutmarks. I've even been the silent coauthor on a couple of papers in which cutmarks were the main focus. (Such is the job of a faculty spouse, I suppose.) And, yes, you saw it coming, I've supervised a hand full of undergraduate honors theses, masters theses, and PhD theses where this was a strong element. And, I helped build a lab designed to look at these suckers.
And when I look at the pictures of the marks on the bones shown in this paper, I see stone tool cutmarks.
But given that stone tool cutmarks are marks made by rocks on bones .... we just can't be sure. But it is cool nonetheless.
The authors of the paper conclude:
The bones presented here are the earliest evidence for meat and marrow consumption in the hominin lineage, pre-dating the known evidence by over 800 kyr. Pending new discoveries, the only hominin species present in the Lower Awash Valley at 3.39 Myr ago to which we can associate this tool use is A. afarensis5,15. Whether A. afarensis also produced stone tools remains to be demonstrated, but the DIK-55 finds may fit with the view that stone tool production pre-dates the earliest known archaeological sites and was initially of low
intensity (one-to-a-few flakes removed per nodule) and distributed in extremely low density scatters across the landscape such that its archaeological visibility is quite low16. The evidence presented here offers a first insight into an early phase of stone tool use in hominin
evolution that will improve our understanding of how this type of behaviour originated and developed into later, well recognized, stone tool production technologies.
We will need more to be certain of this dramatic assertion, but part of the process is publishing the observations that we have. We would also like to see some of the cutmarked bones found in situ in an excavation. Perhaps in time...
Citation for the paper:
McPherron, S., Alemseged, Z., Marean, C., Wynn, J., Reed, D., Geraads, D., Bobe, R., & BÃ©arat, 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
Other sources cited:
Brooks, A. and G. Laden. 1994. The Effects of the Landscape on the Archaeological Record of Foragers: Contrasting the Kalahari and the Ituri Rain Forest. Paper presented at the Society of Africanist Archaeologists, Bloomington.
Dominquez-Rodrigo, Travis Pickering, Sileshi Semaw, and Michael Rodgers. 2004. Cutmarked bones from Pliocene archaeological sites at Gona, Afar, Ethiopia: implications for the function of the world's oldest stone tools. Journal of Human Evolution, 48:2(109-121).
Panger, M. A., Brooks, A. S., Richmond, B. G. & Wood, B. 2002. Older than the Oldowan? Rethinking the emergence of hominin tool use. Evol. Anthropol. 11,(235-245)
Tappen, M. and J.W.K. Harris. 1995. Comment on possible cut marks and taphonomic history of Senga 5A in the Western Rift Valley, Zaire. Journal of Human Evolution. 29:5(483-486).
Tons of questions about this:
800,000 years is a pretty big leap backwards, don't you think? Wouldn't this finding imply that have we been missing/not looking for evidence of tool use between this find and the more-accepted "earliest" dates?
In your work, do you distinguish between "stone tools" and "stones used as tools"? In other words, is it possible that these marks would be evidence of use of unworked stones on bone, rather than evidence of a deliberate crafting of a tool specifically for a use? Does the paleontology community distinguish between those two states? Perhaps this is why the "tools" themselves are not evident (because they're "just stones")?
How would you place this finding in the context of the use of stones by modern chimps? Does it indicate a. afarensis was more dexterous than the modern chimp? Or smarter?
Don't know why this has set off my bullshit detector...maybe it's the claim that out of 3.4 million years worth of artifacts, marks like this are "never" found in a setting other than use of tools by hominids. I'm always leery of categorical statements like that.
It will be interesting to follow the arc of this discovery. An interesting case study on how extraordinary claims are made, evaluated, and either accepted or rejected. I hope the authors have "girded their loins", so to speak.
The earliest "stones used as tools" may be the Ft. Ternan rocks which look like chimpanzee nutting stones ard IIRC are about 14.5 mya. The "stone tools" we are talking about here are flakes made using your basic flint knapping techniques.
It does not change much with chimps vs australopiths in general, becuase at 2.6 mya when we had stone tools being made, we pretty much had australopiths. Which is why I originally proposed years ago that this evidence would be found.
The 800K gap is big, but for that time period, these things happen.
I'm also wondering how you define the boundary cases of made tool versus found rock. I went through a flint-knapping phase (five years old, plus school trip to archaolody museum while living in a flint area), and you can get a tolerably useful edge just by chucking a flint at a bigger rock until it shatters. How do you tell whether a crude tool is deliberately engineered, or just the result of natural processes? Experimenting (until the maternal veto came into play), I managed to make functional knives, choppers and scrapers using several different techniques, but I already had knowledge of non-flint tools and had seen some museum pieces. However, even with those as goals, it took quite a while to refine my work towards the actual museum pieces I'd seen - my initial essays, although adequate functionally, were rather awkward to use and looked like nothing so much as shards and lumps of broken rock!
sorry for the ot but ive been looking for the vid that starts on mt everest and travels out into the universe and back. anyone?
If you smash a bunch of rocks together, even good materials for making stone tools, you don't get more than a very small percentage with striking platforms of 90 degrees or less. If you make stone tools more systematically (and we are talking about the oldowan here, just flakes mostly) you don't get striking platforms of more than 90 degrees. "real" flakes tend to have well defined bulbs of precussion. The total usable cutting edge on the random pieces is usually very low, like 15 percent or so, while on the real flakes it ranges from low to high, with many being high.
Thus, it may be possible to find a "natural flake" but it is virtually impossible to find a "natural assemblage."
mikeg, does this suggest that 'everest' is not in the Universe?
yes, poor phrasing
I recall seing a programme a while back talking about arrow heads that were made in Africa long before most people had theorized homids made tools. Sqadly I don't recall the details, but that we probably haven't been looking at numerous things with the correct perspective. I just find it very cool that our evolution as a tool using species goes back further than folks thought. :)
mikeg, is this the one you are looking for: http://scienceblips.dailyradar.com/video/the-known-universe-by-amnh/
thank you larian, that's the one
Off topic, but Greg I understand only a small percentage of dinosaurs have been found to date, so there is plenty of science for new Docs to look forward to if they go into the field.
Is it the same for the study of hominids? Not specifically discovery of new species, but the what, who, when, why and how of hominids. My guess is that there is a wealth of science remaining for students who want to enter those types of studies. Is there speculation about this that you know of?
As I understand it, the habitats that hominids occupied did not lend themselves to fossils or even very good preservation. Same for most members of the primate order.
@Pilty, please indicate your Poe with some sort of smiley. I'd hate to think someone who actually believed that BS would actually have the ability to read this blog and know what it's saying.
@mikeg, you are welcome.
@pinky: If there's a natural history museum near you with a hominid fossil collection (or even a collection of replicas) you could have a look and if you're lucky you'll even have a genuine resident expert you can talk to at length about what's happening. I'm not saying don't as Greg - it's just much easier if you can talk to someone. (So go stalk Greg if you're in his neighborhood.) At the very least you'll get some idea of what real fossils look like - they really don't look like much. Most fossils of land animals are just fragments which are a tiny percentage of the animal's skeleton. The assembled dinosaur bones you see in movies and some museums are misleading; most of them are made up of parts cast from many different finds and even some parts invented by an artist because there weren't similarly sized parts from other specimens. When it comes to hominids I often marvel that people can classify some of those fragments; they've got to know their bones exceptionally well. I'll have to admit I wasn't terribly good at "name that animal" in my comparative vertebrate anatomy class; even bone fragments of common existing species don't look like much to me.
I remain skeptical not that these are cut marks made by stone flakes, but by the dating.
The first manufactured stone tools were not flakes. If this is a singluar find, maybe the person who did it got a stone flake by accident or luck and used it for a long time.
Or maybe the person who did it was just ahead of his/her time by a couple of million years. Such things happen, even today. Getting people to appreciate the importance of new ideas is sometimes exceedingly difficult.
The first manufactured stone tools were not flakes.
As far as I know, the were.
Maybe I am confused as to what a flake actually is.
Are the mode 1 stone tools "flakes"? I thought that "flakes" were mode 2 and later.
If you whack two stones of just about any kind together, you will get some pieces with edges that are sharper than the original stones. I am thinking like the stone tool on the right side of the first picture. Is that a "flake"?
I thought for a flake you needed a high aspect ratio.
In this case, wikipedia is not your friend.
The "Oldowan choppers" depicted are "mode I' oldowan cores. The pieces you see missing here are flakes.
There are no stone tool industries where the stones are just whacked together. There are a number of "eolithic" assemblages of rocks that are not human/hominid made, but entirely natural, and mistaken for real industries back in the day before replicative experiments were ever done. They are to be disregarded. They are the bigfoot, the UFOs, the woo, and the chain rattling poltergeists of archaeology.
Mode I/Oldowan (and related) industries are known from 2.6 mya and later, with nothing earlier at all.
the dating of the bones is an issue as long as they come from the surface. But there are reasons to accept the date, as is often the case with surface material. Hell, most of the Tanzanian material of Afarensis consists of surface finds. So, a surface-known hominid was making surface-find cutmarks!
Thanks MadScientist I appreciate the reply. I wish I could travel to a natural history museum, but there is not one close and I am not able to travel for physical reasons.
I have read the web sites of some quality museums, such as the Smithsonian. Adding a bit of synergy to your suggestion, I think I'll email the people there with my questions on natural history. They may have the time to answer them.
One of my fantasies was to spend at least two weeks going through the Smithsonian. Unfortunately I waited too long to do it.
> Does it indicate a. afarensis was more dexterous than the > modern chimp? Or smarter?
While A. afarensis had a brain about the size of a chimp, I think it may have become specialized in a way different from a chimp because the front limbs were no longer being used for ground locomotion. I don't know what afarensis was doing with its hands but I'm fairly sure they hadn't invented pockets yet. In the article I read the authors seemed confident that these guys could have been tool users (at least as intelligent as chimps) but were less confident about them being tool makers. It seems to me that since we have about 1.5 million years before leaving Africa as full tool users, the time line is about right for more sophisticated tool use anyway.