john hawks weblog

paleoanthropology, genetics and evolution

Neandertals

  • 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

    Synopsis: 
    An article about Middle Paleolithic subsistence brings a focus on meat acquisition
  • Neandertal anti-defamation files, 17

    Tue, 2013-01-01 17:30 -- John Hawks

    Let no one say that I'm an uncritical voice about the many advantages of releasing preprints. They do have their downsides. Lack of editing is one.

    Here's a passage from a new preprint from Peter Waddell and Xi Tan, "New g%AIC, g%AICc, g%BIC, and Power Divergence Fit Statistics Expose Mating between Modern Humans, Neanderthals and other Archaics":

    The apparent lack of Denisovan alleles on the X chromosome suggested that some of these archaic interbreeding events were male biased, that is archaic males mating with modern females (Waddell, 2011). This was formerly dubbed the “archaic Ron Jeremy” hypothesis, after the well-known American thespian. Formerly known, because a journal editor has recently urged us to alter our manuscript, to avoid confusion with a “Ron Jeremy Event”, which they referenced to the Urban Dictionary. The new synonymy is the “lecherous archaic man” hypothesis.

    I'll return to the argument in the paper later, I just wanted to consider the question of Neandertal similarity to well-known thespians. This is a followup to another preprint from last 2011, which addressed the question of male-biased gene flow into the ancestry of Papua New Guinea from Denisovan peoples ("Homo denisova, Correspondence Spectral Analysis, Finite Sites Reticulate Hierarchical Coalescent Models and the Ron Jeremy Hypothesis"). From that preprint:

    While the origin of the unusual features of the NSYFHP pattern is just a hypothesis at this stage, it is testable and deserves a name, so we call it the “Ron Jeremy hypothesis” (after the accomplished American thespian Ron Jeremy, who is adroit at debauching modern young women, whose father’s might well call him a Neanderthal or a Denisovan, and who looks remarkably like reconstructions of these archaic humans in museums, including being very big boned).

    Big boned.

    Similarly, we may refer to the low frequency of the NSYFHP on the X chromosome as “Ron’s Grandfather hypothesis” which is the mixing of the Denisovan lineage with an even more ancient hominid lineage due to a male biased infusion.

    Obviously we badly, badly need a better system of terminology to discuss the relationships of archaic human groups, including MSA and earlier Africans, which we now understand to have been subject to recurrent gene flow. Male-biased gene flow has often happened in human groups, sometimes due to warfare or the dominance of elites, sometimes as a simple function of greater male dispersal. Male-biased gene flow also appears to characterize orangutan population history, but not chimpanzees, so it depends on species-specific aspects of population structure and dispersal strategies.

    We unfortunately have a 150-year history of looking at Neandertals, and secondarily at other archaic human groups, as strange evolutionary dead-ends. When faced with the evidence that these ancient people are among our ancestors, some scientists have turned first to the idea that mating among ancient people was exotic and strange. Hence the "Ron Jeremy" angle.

  • "Decoding Neanderthals" to be broadcast

    Sat, 2012-12-22 16:08 -- John Hawks

    NOVA on American PBS stations has produced a new documentary about Neandertals: "Decoding Neanderthals". They have just announced that it will be broadcast January 9 on most stations.

    Here's the program description:

    Over 60,000 years ago, the first modern humans—people physically identical to us today—left their African homeland and entered Europe, then a bleak and inhospitable continent in the grip of the Ice Age. But when they arrived, they were not alone: the stocky, powerfully built Neanderthals had already been living there for hundred of thousands of years. So what happened when the first modern humans encountered the Neanderthals? Did we make love or war? That question has tantalized generations of scholars and seized the popular imagination. Then, in 2010, a team led by geneticist Svante Paabo announced stunning news. Not only had they reconstructed much of the Neanderthal genome—an extraordinary technical feat that would have seemed impossible only a decade ago—but their analysis showed that "we" modern humans had interbred with Neanderthals, leaving a small but consistent signature of Neanderthal genes behind in everyone outside Africa today. In "Decoding Neanderthals," NOVA explores the implications of this exciting discovery. In the traditional view, Neanderthals differed from "us" in behavior and capabilities as well as anatomy. But were they really mentally inferior, as inexpressive and clumsy as the cartoon caveman they inspired? NOVA explores a range of intriguing new evidence for Neanderthal self-expression and language, all pointing to the fact that we may have seriously underestimated our mysterious, long-vanished human cousins.

    I make an appearance on the show -- and that's my voice in the trailer talking about the "mother of all public relations problems" that Neandertals have faced.

  • Mandibles of Neandertals and modern humans

    Mon, 2012-11-12 22:17 -- John Hawks
    Synopsis: 
    Lab station presenting modern human and Neandertal mandibular features

    Many of the differences between Neandertals and modern humans can be found in the face and jaw. Neandertals had relatively tall faces, and substantial prognathism of the midface. To describe more fully: Neandertal faces were tall from the chin to the browridge, and they extended far forward relative to the ears.

    These aspects of facial anatomy are reflected in the Neandertal mandible. The part of the mandible that includes the alveoli for the roots of the teeth is called the corpus. The corpus tends to be thicker and stronger in Neandertals than in most living people. It also tends to be taller, with a greater distance between the inferior border of the mandible and the teeth.

    At the front of the mandible is the mandibular symphysis. In modern humans, there tends to be a projecting triangle of bone, which we call the chin, but in technical terms is known as the mental eminence. Few Neandertal fossils have a chin. Most, like earlier hominins, have a slightly receding mandibular symphysis.

    The part of the mandible that stretches upward from the corpus to connect to the temporal bones is called the mandibular ramus. The shape of the Neandertal tooth rows is basically the same as in the human jaw. But the mandibular ramus is relatively more posterior, so that there is a gap between the third molar and the anterior border of the ramus. This gap is called a retromolar space, and it reflects the strong midfacial prognathism of the Neandertal skull.

    What to do: This station has several Neandertal partial mandibles, from the site of Krapina, Croatia. There is one early modern human mandible from Skhul, in present-day Israel. These are comparable in age (Krapina is 120,000 years old, Skhul is around 100,000 years old). Compare these to the recent human mandibles at the station and consider how these Neandertals fit relative to human variation.

  • Neandertal piece

    Tue, 2012-11-06 16:53 -- John Hawks

    A piece on my desktop that I've been meaning to blog is by Sarah Zielinsky in National Geographic News: "Neanderthals ... They're Just Like Us?". Several good quotes including one from me, here's one from John Shea:

    "It's increasingly difficult to point to any one thing that Neanderthals did and Homo sapiens didn't do and vice versa," said John Shea, an archaeologist at Stony Brook University in New York.

    "These Ice Age people, both Neanderthals and Homo sapiens, survived, thrived, and increased their numbers under conditions that would probably kill people nowadays, even ones that are equipped with modern survival technology."

  • Mailbag: The Eemian: what gives?

    Wed, 2012-10-31 21:12 -- John Hawks

    I wandered into your site after searching for Eemian and human evolution.

    The general consensus is that anatomically modern humans were in Africa 150-200K year ago. During the Eemian interglacial these humans presumably had similar opportunities to migrate and develop agriculture as humans did during the Holocene. Yet apparently they didn't.

    Do have any thoughts on why this is so?

    Of course, a smaller population base at the beginning of the Eemian than at the beginning of the Holocene might account for this but I would think that with favorable climatic conditions a small population at the start would rapidly increase.

    Another reason might be that anatomically modern humans at the beginning of the Eemian lacked something in the neurological wiring to build modern culture.

    Thanks for writing. Indeed, this very question has interested archaeologists for a long time. The multiple independent origins of domestication and agriculture seem to have a demographic explanation. That means that the Eemian, with its environmental profile so similar to the Holocene, might be expected to have given rise to the same events. Surely Eemian west Asia was more similar to Holocene west Asia than the latter was to Holocene Mexico.

    Archaeologists' explanations are basically as you describe, although I could add a few:

    1. Maybe the Eemian wasn't really so similar to the Holocene, despite appearances.
    2. The technology in pre-Eemian times may not have allowed population growth in response to the ameliorating climate to the extent that Upper Paleolithic-era technologies did prior to the Holocene.
    3. The cognitive abilities of Eemian-era humans may not have enabled effective response to changing climate.
    4. The cultural systems of pre-Eemian times may have been more highly based on population regulation/limits to growth, thereby enabling the population to respond without the overgrowth that necessitated sedentism and ultimately domestication of plants.
    5. Demographic intensification in Africa and resulting mass migration DID happen in the Eemian, and we call this the out-of-Africa event.

    I will note that there is now some evidence of intensive collection of cereals in tropical Africa before the Eemian, so this problem may yet become more complex. One of the reasons I follow the Holocene domestication literature so closely is to try to perceive what social dynamics were shared among terminal Pleistocene peoples -- because some critical factors must have been absent pre-Eemian, but we don't know which!

  • Mailbag: The Neandertal species question

    Thu, 2012-10-25 15:35 -- John Hawks

    Hello Dr. Hawks, I understand your a busy man so my question will be brief. I learned in my biology class that two different species can not interbreed and produce fertile offspring. If this is the case, how can we carry 4% Neanderthal genes? If they were a different species we should have not been able to crossbreed. Could you please explain this if you have time?

    They weren't a different species.

  • Mailbag: Volcanic winter for Neandertals, continued

    Tue, 2012-10-16 16:22 -- John Hawks

    I happened upon your weblog a couple of months ago and find it fascinating, thanks for your effort. If the timeline/data of http://www.sciencedaily.com/releases/2012/10/121016084936.htm is accurate do you think it could be a contributing factor in the demise of the Neandertals?

    Thanks so much for your kind words!

    I wrote about the Campanian Ignimbrite a couple of years ago, when a group of Russian researchers suggested the resulting climate change as a factor in Neandertal disappearance:

    http://johnhawks.net/weblog/reviews/climate/paleo/neandertal-volcanoes-2...

    I'm skeptical of any particular event, considering how the Neandertals survived many climate fluctuations long before this time, with more rudimentary technology. I would say that several archaeologists I respect think that the climate change was a factor acting together with increased stress from competition with modern human populations. Personally, I want to know how much mixture was going on within Europe before I am willing to believe a lot of competition was happening on the ground. Anyway, this field is definitely developing fast. I'll have something new up about coexistence and possible competition in Italy sometime soon.

  • Liveblog of ScienceNOW on Neandertals, Dikika

    Wed, 2012-10-10 22:09 -- John Hawks

    Now watching the NOVA ScienceNOW about "What makes us human".

    9:06: "The idea of another species of humans sharing our cities isn't that far-fetched. 30,000 years ago, there were at least four different kinds of humans sharing the earth, including the Neandertals"

    The introduction to Neandertals isn't bad, although I really don't like it when people say "the ones who stayed in Africa became us" -- that minimizes the contribution of other people, and glosses over the possibility that some ancient Africans didn't become "us", or were among the ancestors of some Africans but not all.

    9:08: "Daniel Lieberman from Harvard looks for answers in the way human heads evolved" -- Lieberman: "What makes you different from Neandertals is basically above the neck."

    9:09: Now Pogue is showing himself in a makeup studio being made into a Neandertal character. Back to Lieberman explaining how the Neandertal head is different from ours. It's really interesting to hear him describe this, because the description is completely typological -- there's no conception here of variation within Neandertals or within humans.

    9:11: OK, the makeup transformation is complete. I don't want to cast aspersions on the artists, but the result doesn't compete with the makeup jobs on Face/Off.

    Pogue goes walking down a city street. I don't see anybody noticing..but of course there's a cameraman following him around.

    9:13: Differences in the shape of the brain. Lieberman "wouldn't bet his mortgage" on human brains being better than Neandertals.

    Now Pogue is presenting several just-so stories about why we were superior to Neandertals. He dismisses these as "speculation" and starts talking about the Neandertal genome. We see a Max Planck scientist grinding up some bone with a Dremel tool.

    9:15: Yay, Ed Green!

    Green: "They had sex, they had descendants, we find this trace in our DNA today. Amazing."

    9:18: This is the fourth show I know of where they have a presenter get their DNA sampled to find the Neandertal fraction. It's really cool that they are getting this news out there.

    Green shows Pogue a part of chromosome 12 where he has a Neandertal nucleotide. They're showing a laptop screen with a slot machine-like display of nucleotides. I suppose it was really a blank screen and they did it in post-production. Either that, or I have to get the slot machine DNA typing program!

    9:20: "We may not see Neandertals among us, but they are still here, within us."

    Still walking down the street. An older lady seems to have decided Pogue is some kind of freak.

    Oh, no! An animated Neandertal in drag! She/he is putting on makeup (this is about the shells and pigments associated with Neandertals). I have only this to say: Through the Wormhole has way better short animations than ScienceNOW.

    Whew, that was over quick. Now he's on to the origin of language.

    9:22: It's Dave Frayer! He's got a suitcase with skulls inside. Man, it would be cool if it were like the one in Pulp Fiction!

    OK, well, it's cooler to have one with skulls inside, I guess.

    Going through Homo erectus brain size. A symmetrical stone tool becomes a way to look into the cognitive abilities of early Homo.

    9:26: On to Dietrich Stout, who is discussing the pathways in the brain used for stone tools. He works with Bruce Bradley, expert stone knapper, who is giving Pogue a lesson in toolmaking.

    With toolmaking we're looking at complex, sequential thought. Bradley: "Because what are we looking at with language, it's complex sequential thought"

    9:29: Now Cynthia Thompson, who is looking at people with brain injuries that lead to aphasia. "Agrammatic aphasia patients share a common characteristic: damage to the left hemisphere of the brain, which contains an area called Broca's area...does Broca's area have anything to do with stone toolmaking?"

    9:31: Going into a scanner, where people are watching stone toolmaking via a projector, on the argument that watching an activity and doing the activity involve the same brain area. "Watching the video of simple choppers resulted in mild activity in Broca's area, but watching the video of making a handaxe caused four times as much activity"

    9:34: A short interlude on babies learning language.

    9:35: Looking at babies learning to laugh. Gina Mireault is studying babies smiling and laughing. "What we found with these very young babies, is that when we tell parents to make their babies laugh, they do some very outrageous things. Laughter is irresistible"

    9:37: Now at the Cincinnati Zoo to see if animals laugh. Pogue tickles a penguin -- "he's laughing" -- "no, that's the noise they make when they want to breed"

    Pogue is really talented at this part, he totally commits himself to being silly in the name of science.

    Marina Davila-Ross is studying primate laughter. They are at the Stuttgart Zoo with gorillas. She collected sounds from all the great apes being tickled. Super cool audiogram images of the laughter sounds going from most distant -- orangutans -- to humans across the phylogenetic tree. Gorillas always use the same kind of panting laughter, as a part of horseplay.

    9:42: Now with psychologist Michael Owren, looking at acoustic models of laughter sounds in people.

    9:43: Pogue asks a great question: "How did that make me have more babies?" The program gives an answer (for laughter and social relationships) but it's great that they edited it to emphasize this question.

    9:44: Zeray Alemseged in Ethiopia: "I went to start the first Ethiopian-led project in paleoanthropology ever, but it wasn't easy". The show gives a great short biography of Alemseged. This is an awesome segment.

    9:48: Now at Dikika. They do a great job illustrating the discovery of the skeleton.

    9:50: Don Johanson discussing how we "did not instantly become human".

    9:51: "Day after day, for six years, Zeray chipped away at the piece of stone." They're comparing the Selam teeth to apes and humans, inferring its age and pattern of development. The show has him at a computer with Fred Spoor examining CT data.

    9:53: Describing the hoopla that arose upon the publication of the Dikika skeleton. This has been a great 12-minute segment on Alemseged.

    9:55: And that's the program. Very well done, a range of segments that go together very naturally. They really did save the best for last, but really everyone in the program did a great job.

    Synopsis: 
    The magazine program has segments on Neandertal DNA, language evolution, and Zeray Alemseged
  • A Neandertal mortuary in Spain?

    Tue, 2012-10-09 19:53 -- John Hawks

    El Pais has a fascinating story about the Paleolithic sites in the Lozoya river valley: "A Neanderthal trove in Madrid".

    It was on the floor of Des-Cubierta that the Neanderthal must have placed the dead body of a small child aged two-and-a-half to three years old. They placed two slabs of stone and an aurochs horn on top, and set the body on fire. [Enrique] Baquedano explains that they found some of the child's teeth - they call it a little girl, although they have no scientific evidence of its gender - as well as a piece of coal that turned up just a few days ago and which will enable precise dating. "Complete burials, with a clear structure that allows [researchers] to reconstruct behaviors, is a very rare thing in any part of the world," says [Juan-Luis] Arsuaga, who is also co-director of the excavations at the major prehistoric site of Atapuerca.

    This one sounds like an incredible context, if it really is as described.

    Arsuaga is author of The Neanderthal's Necklace.

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Neandertals

For years, I've worked on their bones. Now I'm working on their genes. Read more about the science studying these ancient people.

Denisova

From a finger bone of an ancient human came the record of a completely unexpected population. My lab is working on the science of the Denisova genome.

Acceleration

The advent of agriculture caused natural selection to speed up greatly in humans. We're uncovering some of the ways that populations have rapidly changed during the last 10,000 years.

Malapa

Just outside Johannesburg, the Malapa site is producing some of the most exciting finds in human evolution. This site is the headquarters of the Malapa Soft Tissue Project.