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  • Slow cooking Neandertal subsistence

    Tue, 2013-01-01 20:12 -- John Hawks

    During the past couple of years, new evidence has really shifted our view of Neandertal diet. Even three years ago, it was not unusual to hear Neandertals described as "hypercarnivores", more heavily reliant upon meat than any living hunter-gatherers, except possibly for Inuit who live on seal meat and whale blubber.

    The idea that Neandertals had diets with a very high fraction of meat -- maybe as high as 90-95% meat -- came from analyses of stable isotopes. I reviewed some of the stable isotope work on Neandertal diet in 2005 - "Neandertals noshed on mammoth meat?", "Neandertals: gone fishin' or not?". Here at the beginning of 2013, stable isotopes are well worth another review here on the blog.

    The extreme view of Neandertals as hypercarnivores has been softened by new evidence from several sources. Phytoliths and starch grains from Neandertal dental calculus have shown a wide variety of plants were consumed by Neandertals at least occasionally. Meanwhile, the starch grains have not only documented consumption of grains and tubers, but have also shown that Neandertals were cooking those plant foods. I wrote about the phytolith and starch granule discoveries by Amanda Henry and colleagues [1] last year ("Tartar control and Neandertal plant use").

    A new article by John Speth in Before Farming reconsiders the archaeological record of game exploitation by Neandertals and early modern humans in the Near East [2]. Speth begins with a short review of how Neandertals gradually came to be known as hypercarnivores -- in spite of many archaeologists' insistence that they must have been incompetent in various ways. After some discussion of the limits of the archaeological record, he notes that the zooarchaeological record doesn't tell us about the quantitative contribution of meat to the diet. In short:

    Lots of gazelle bones doesn’t necessarily mean lots of gazelle meat per capita per day.

    He illustrates this point with a historical case, the excavation of trash heaps from Fort Ligonier, Pennsylvania, occupied by the British during the French and Indian War. There, the total meat yield represented by animal bones was estimated at only 4,000 pounds, a tiny fraction of the meat ration known to have been issued to soldiers. The point of the example is that many biases prevent the accumulation and discovery of animal bone, even in historic contexts. The Paleolithic record of faunal exploitation can represent only the merest fraction of animal carcasses that were actually handled or consumed by ancient peoples. Biases guarantee that this record will be unrepresentative in ways that we may be poorly able to assess.

    Speth addresses the idea that Middle Pleistocene people consumed a very high fraction of meat by emphasizing that a diet of lean meat is unsustainable at such a level. If Neandertals' animal consumption was as high as Inuit peoples, then they must have been eating a high fraction of fat somehow:

    The Inuit or Eskimos provide a classic example of peoples whose traditional sustenance was provided almost entirely by meat, the diet commonly envisioned for cold-climate Neanderthals. But when looked at quantitatively, Inuit diet was actually composed primarily of fat, not lean meat, with the protein contribution seldom surpassing about 35 per cent of their calories, and usually lower, closer to 25 per cent. Pemmican, the traditional mainstay of Native Americans and First Nation peoples (‘Indians’) inhabiting the Great Plains of mid-continental North America, was a mixture of rendered fat and dried, pulverized lean meat, the mix carefully prepared so that the pro- tein component did not exceed 25–30 per cent of total energy (eg, Stefansson 1956; Speth 2010). In habitats where plant foods are neither abundant nor available for long periods of the year, and particularly for foragers in such habitats who do not store foods, fat becomes the principal non-protein macronutrient for much of the year. Foragers in the northern latitudes did obtain some carbohydrates by consuming fermented stomach contents of reindeer and ptarmigan, and sometimes inner bark (cambium), as well as small quantities of berries during the summer months (Eidlitz 1969; Gottesfeld 1992; Östlund et al 2009; Sandgathe & Hayden 2003; Zackrisson et al 2000). Until fairly recently, stomach contents were actually considered a delicacy (often referred to as ‘Eskimo ice cream’), not an emergency resource resorted to only when all else failed (Starks 2007; Speth 2010). Unfortunately, we lack quantitative data on the actual amounts that were consumed, how those amounts varied over the year, and whether men and women had comparable access. Did Neanderthals also con- sume fermented stomach contents? If so, would such a practice have had any detectable impact on their unusually high nitrogen isotope values?

    Through the middle of the article, Speth provides a detailed account of the biases due to taphonomy and ancient behavior that apply to faunal collections in Middle Paleolithic contexts. Many of these factors, such as biases in transport of different size animals, are well-known to archaeologists, but Speth's review will be useful for those who may not have studied the issue. The value of this part of the article is in its application of prey transport and landscape use to the unique geography of the Near East. Here, Middle Paleolithic peoples hunted amid water scarcity and temperature regimes that were very different from those found in Southwestern Europe. Yet by several indicators, the Middle Paleolithic population in both areas was relatively dense and successful.

    Speth reminds us that ancient hunters were active agents who made choices in their hunting strategies. Some of those choices may have been influenced by landscape use and prey abundance, but others are less easily predictable in such terms:

    The Hadza, one of the most thoroughly documented modern foraging populations, offer another interesting example. Wildebeest are one of the most abundant prey available to Hadza hunters, but they commonly avoid wildebeest in favour of zebras. Why? According to Hadza informants, the fat from wildebeest is hard and sticks to one’s teeth and palate,while zebra marrow and back-fat, especially the yellow subcutaneous deposits near the rump, are far more desirable (Oliver 1993:217; Selous 1907:220; Speth 2010:66–70). Were we to assume that Hadza hunters took prey in direct proportion to their availability on the landscape, our conclusions would be very wide of the mark.

    Back to the problem of lean meat: Hunter-gatherers in ethnographic and historical records have used boiling to degrease bone. This allows the use of the fat from inside the cancellous structure of the bone, which is a key resource supporting the use of lean wild animal meat. Boiling or slow-cooking using heated stones has been applied by many peoples around the world, and tends to leave a very distinctive archaeological trace -- the heated rocks, lined pits dug to enclose the slow-cooking mass, all show up in the archaeology. These techniques were not used by Middle Paleolithic people, or if such people used heated rocks, they did not use them terribly extensively. Stone boiling became common only later in the Upper Paleolithic of Europe.

    But Speth discusses other means of boiling, including the use of skin and bark containers. These are expedient and perishable, yet filled with water will effectively contain boiling liquid over hot coals or indirect flame. Whether such techniques were used by Neandertals remains speculative. The suggestion is latent in the identification of cooked starches within Neandertal dental calculus. If they were capable of cooking grains in moist heat, they must at least have been using bark packets or some other style of slow-cooking. The rendering of fat from bone by boiling in perishable containers would not take much additional innovation, and would have been energetically and nutritionally very advantageous.

    As I was discussing this with friends a couple of weeks ago, it occurred to me that the combination of cooked grains and meats within an animal bladder is a recurrent feature of the cuisine of Northern Europe. Neandertal haggis.

    References

    1. Henry AG, Brooks AS, Piperno DR. Microfossils in calculus demonstrate consumption of plants and cooked foods in Neanderthal diets (Shanidar III, Iraq; Spy I and II, Belgium). Proceedings of the National Academy of Sciences [Internet]. 2011;108:486–491. Available from: http://dx.doi.org/10.1073/pnas.1016868108
    2. Speth JD. Middle Palaeolithic subsistence in the Near East: zooarchaeological perspectives – past, present and future. Before Farming. 2012;2012(2):1.
    Tags: 
    Neandertals
    diet
    zooarchaeology
    subsistence
    meat
    Synopsis: 
    An article about Middle Paleolithic subsistence brings a focus on meat acquisition

  • Digestive evanescence

    Sat, 2012-08-18 19:25 -- John Hawks

    Also in The Guardian, "Strange but true: science's most improbable research" includes some taphonomy:

    If you like shrews, especially if you like them parboiled, you'll want to devour a 1994 study published in the Journal of Archaeological Science. Called Human Digestive Effects on a Micromammalian Skeleton, it explains how and why one of its authors – either Brian D Crandall or Peter W Stahl; we are not told which – ate and excreted a 90mm-long (excluding the tail, which added another 24mm) northern short-tailed shrew (Blarina brevicauda).

    I've always been fascinated by the evidence for hyena digestion on Pleistocene faunal remains -- they crunch the bones and their stomachs etch the pieces into all manner of lozenge-like detritus. But I hadn't thought much about human shrew-eating and the total dissolution of tiny toe bones.

    Because who does think about that, really? I mean, besides zooarchaeologists.

    Tags: 
    taphonomy
    zooarchaeology

  • Warp and woof

    Thu, 2012-05-24 23:44 -- John Hawks

    James Gorman stirs the pot on dog domestication, by comparing the new review article by Greger Larson and colleagues [1] with Pat Shipman's American Scientist piece [2] ("What-If and What-Is: The Role of Speculation in Science"). This is a complex story, and Gorman lines the two papers in opposition to each other -- the data-focused paper by Larson and colleagues, which ultimately has an ambiguous conclusion, opposed to the speculative paper by Shipman, with relatively little empirical data and a strong prediction.

    I won't go into the whole argument, which you can read at the link, but it boils down to whether the archaeological evidence shows early dogs or not.

    If dogs were watching us too, that would have added survival value to having a partly white eye and thus played a role in our evolution. Fair enough, but the dogs had to be there at that time when humans and Neanderthals overlapped. I asked Dr. Larson about Dr. Shipman’s essay, and I confess I expected he might object to its speculative nature. Not so. “I love speculation,” he wrote back, “I do it all the time.” And, he said of Dr. Shipman’s essay, “it’s a lovely chain of reasoning.”

    But, he said, “it begins from the premise that the late Pleistocene canid remains are dogs. And they are not.”

    I rather like the new Larson paper, but there are some weak points. Dog domestication was a complex process and ultimately we will need a lot more genetic data from zoo archaeology to sort it out.

    References

    1. Larson G, Karlsson EK, Perri A, Webster MT, Ho SYW, Peters J, Stahl PW, Piper PJ, Lingaas F, Fredholm M, et al. Rethinking dog domestication by integrating genetics, archeology, and biogeography. Proceedings of the National Academy of Sciences of the United States of America. 2012.
    2. Shipman P. Do the Eyes Have It?. American Scientist. 2012;100(3):198.
    Tags: 
    dogs
    domestication
    zooarchaeology

  • Probing bones

    Fri, 2010-10-01 09:09 -- John Hawks

    John Travis gives a conference summary (paywall) of the recent International Symposium on Biomolecular Archaeology. The focus is new technological approaches to studying archaeological sites, and several novel projects are described. I like this one:

    RNA may be considered fragile, but the bone protein collagen is among the best survivors of the ravages of time. RNA can last hundreds of years, and DNA tens of thousands, but collagen apparently sometimes survives for millions of years in a bone. That's why Michael Buckley of Bournemouth University, while working in the laboratory of Matthew Collins of the University of York, both in the U.K., spearheaded a technique to use collagen fragments, or peptides, to identify the species of nondescript bits of bone. Called ZooArchaeology by Mass Spectrometry (ZooMS), the method relies on subtle differences among species in the amino acid sequence, and thus mass, of collagen. For less than $10 a test, scientists may one day be able to take any bit of fossilized bone and identify the genus, or even species, it came from, says Buckley.

    That's most relevant for sites where you only have tiny amounts of animal bone (like the New Guinea sites described yesterday).

    Tags: 
    zooarchaeology

  • Australopithecus afarensis used stone tools

    Wed, 2010-08-11 15:13 -- John Hawks

    UPDATE (2011-09-06) Note: The conclusions of the research were later critiqued, I posted on that criticism after this post.

    Shannon McPherron, Zeresenay Alemseged and colleagues working at the Dikika field site in Ethiopia have found evidence of stone tool use 3.39 million years ago [1]. That's 800,000 years earlier than the previous first-known tool use, and occurs during the existence of Australopithecus afarensis.

    The evidence is a series of cutmarks and one percussion mark on two bovid bones. One is a piece of rib from a large "cow-sized" animal, the other a femur fragment from a smaller "goat-sized" bovid. The analysis goes through several microscopic comparisons to rule out alternative causes for the cutmarks, such as trampling. The key paragraph of the results:

    The cut marks demonstrate hominin use of sharp-edged stone to remove flesh from the femur and rib. The location and density of the marks on the femur indicate that flesh was rather widely spread on the surface, although it is possible that there could have been isolated patches of flesh. The percussion marks on the femur demonstrate hominin use of a blunt stone to strike the bone, probably to gain access to the marrow. The external surfaces of ribs have thin sheaths of flesh, so the scraping marks on the fossil rib suggest stripping off of these sheaths.

    I have some lingering doubts, none of which are very serious, but that point out the need to look harder at other sites. It sure would have been nice if they'd found an anomalous sharp-edged rock nearby.

    The two bones are compelling, but the study does not give much indication of how representative they are. How many similar-sized bone fragments were left at the site? How many were collected? What fraction of "cutmarked" bones does that make? What fraction show signs of trampling and various kinds of post-depositional damage?

    Those questions are essential to answer the "green car" problem. If you don't know this one, it's fairly simple -- a witness reports a green car leaving the scene, and green cars are very rare -- the police think this is a great lead. But blue cars are very common in the city, and there is a small chance that the witness mistook a blue one for a green one. Whether it actually was a green car depends on the actual proportion of green to blue cars, and the actual probability that the witness was wrong.

    In this case, I think there is a very small chance that the marks on these bones could have been produced by processes other than deliberate cutting by a stone tool. But in a sample of hundreds or thousands of bone fragments, a small chance might well happen a couple of times. It's very difficult to quantify this, because archaeologists don't collect every bone fragment. The only real way to address the problem is to find more cutmarks and do other statistics on them -- do they occur where flesh is attached to bone, etc.

    It does seem odd that nobody's identified clear stone tools, which are in later sites a lot more common than cutmarked bones. A tool-user will make many artifacts during her life. (Why "her"? Well, in chimpanzees, it's the females who dominate technology transmission...) We have a lot of australopithecine bones. If this was a long-lasting tradition, we should have found a lot of stone tools by now.

    Maybe it wasn't a long-lasting tradition. Chimpanzee technology is significantly clustered geographically, some of the most interesting behaviors have been observed only at a single field site. If Australopithecus had a similar pattern of cultural diversity, tool use may have been innovated many times without "catching on" over a wide geographic or temporal extent. Here's what McPherron and colleagues conclude along similar lines:

    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 low (16).

    Or maybe we just haven't noticed. Fluvial contexts may have been bad places for Australopithecus to hang out. McPherron and colleagues allude to this explanation for the local absence of tools at Dikika:

    However, stone tool production and consequently archaeological accumulations are not expected at this locality given the sedimentary environment characterized by the palaeo-Awash River emptying into a nearby lake (3, 4). In this relatively low-energy depositional environment, clasts suitable for stone tool production are not present (few particles larger than fine gravel, 8 mm diameter). Within the exposed SH Member, the distance from DIK-55 to cobble-sized raw materials (>64 mm) is ~6 km (at Gorgore; Fig. 1). Thus, in this instance the absence of evidence for stone tool production in the immediate vicinity of the cut-marked bones may reflect landscape-level raw material constraints.

    The research article is accompanied by an essay by David Braun reviewing the find [2]. He stretches a bit, but I think the interpretations he suggests are worth airing. One -- why are there cutmarked bones 6 km from any good source of stone raw material?

    The meat and marrow of large animals must have been a valued resource, because McPherron et al. conclude that the tool users incurred the cost of transporting stones 6 kilometres from where they occurred naturally to the site where the butchery took place. Further costs that were associated with the consumption of carrion, and were apparently worth the risk, include exposure to parasites and competition with large carnivores.

    Two -- what about the "meat-brain" connection?

    This provides exciting evidence of how A. afarensis behaved. At one time, the species was considered to be a relatively primitive hominin, but this perception is being redefined. For example, it now seems that Lucy's kin had body proportions that were more similar to those of humans than of apes (6). Analyses of the hand of A. afarensis show that it had relatively short fingers that would allow the kind of fine-scale manipulation necessary for tool use (7). A recently discovered skeleton from the Woranso–Mille area of Ethiopia suggests that A. afarensis did not have the ape-like, 'funnel-shaped' thorax usually associated with a large digestive tract and low-quality diet (8). Perhaps the findings that these hominins used tools and had a carnivorous component to their diet should not have been so unexpected.

    A 2.6-million-year-old butchery tradition should already have refuted the hypothesis that meat-eating caused the expansion of brain size in Homo. But it was still possible to maintain that the initial Oldowan was insufficiently dedicated, or that the anatomical specializations (e.g., small guts) allowing brain expansion took time to develop, or that as-yet-undiscovered large-brained hominins would be found. Any of these are still possible, but the observations Braun points out pretty much demolish the 15-year-old story of "expensive tissue." Australopithecus seems to have had a small gut, and a bigger brain than chimpanzees. If there was a tradeoff, A. afarensis had already made it.

    Braun didn't mention A. sediba, which adds another wrinkle. A late species of Australopithecus with human-sized teeth. Or (as some prefer), a pre-habilis species of Homo with an Australopithecus-sized brain. What was its diet like? I have a feeling we'll know before too long.

    Meanwhile, I'll be floating for the rest of the year, since I included this as the far-out "bonus" entry in my 2010 New Year predictions! You know, the one that's so bizarre that it seems like it'll never happen. Heh.

    UPDATE (2010-08-11): John Noble Wilford got ahold of some skeptics for his NY Times story on the discovery:

    Still, the discoverers are already being pressed to defend their interpretation that the cut marks on the bones are evidence of stone-tool butchery. Tim D. White of the University of California, Berkeley, one of the foremost investigators of early human origins, said flatly that their “claims greatly outstrip the evidence,” and noted, “We have been working sites in this area for 40 years, and not a single stone tool has been found in deposits of this antiquity.”

    Sileshi Semaw, a paleoanthropologist at Indiana University who was a discoverer of the oldest confirmed stone tools, from 2.6 million years ago, noted in an e-mail message from Ethiopia that researchers had often been misled by bone markings left by trampling animals and other natural causes. “I am not convinced of the new discovery,” he said.

    UPDATE (2010-08-12): Maybe some are looking for more about australopithecine diets. My post from 2005, "Chemistry and early hominid diets" has a good compilation of stable isotope observations and what may explain them. With the cutmark evidence, you can read through the discussion of C4 plant contributions, and think about the grazers that A. africanus may have been eating.

    UPDATE (2010-08-16): Science Friday with Ira Flatow covered this story last week, including commentary by Alemseged and David DeGusta, who suggests that the marks may be crocodile bite marks. Doesn't look like it to me, but as I wrote above, I'd like to see statistics on a few hundred damaged bones to see the probability that an arbitrary one will look like stone cutmarks.

    References

    1. McPherron SP, Alemseged Z, Marean CW, Wynn JG, Reed D, Geraads D, Bobe R, Bearat HA. Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia. Nature [Internet]. 2010;466:857–860. Available from: http://dx.doi.org/10.1038/nature09248
    2. Braun DR. Palaeoanthropology: Australopithecine butchers. Nature [Internet]. 2010;466:828. Available from: http://dx.doi.org/10.1038/466828a
    Tags: 
    Dikika
    Lower Paleolithic
    Pliocene
    A. afarensis
    taphonomy
    archaeology
    Ethiopia
    Oldowan
    stone tools
    Africa
    zooarchaeology
    Synopsis: 
    A report finds cutmarks on fauna from Dikika, Ethiopia, 3.4 million years ago.
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