Tag Archives: Human Evolution

The Untermassfeld Controversy

Ancient European humans and their near relatives such as late Homo erectus, “archaic” Homo sapiens, Neanderthals, and Denisovans all come from an African stock. While some of the variation we see in these late members of the genus Homo certainly arose in Eurasia, these groups all represent either African populations or stems coming off an African trunk.

There are two chronologies proposed for the early occupation of Europe, for the time before these branches are clearly visible. The “long chronology” has human relatives in Europe perhaps as far back as two million years, and the “short chronology” has these human relatives at around a half million years ago or later.

The truth is probably this: Continue reading The Untermassfeld Controversy

The Oldest Human Bones, Jebel Irhoud, Morocco

You’ve heard to story. I’m here to give you a little context.

A pretty typical early handaxe, made by a Homo erectus. This was a big flake made from a bigger rock. The big flake was subsequently flaked to make this handaxe. The word “handaxe” can be spelled about nine different ways.
But in case you haven’t heard the story, this is from the press release which is, so far, the only information generally available:

New finds of fossils and stone tools from the archaeological site of Jebel Irhoud, Morocco, push back the origins of our species by one hundred thousand years and show that by about 300 thousand years ago important changes in our biology and behaviour had taken place across most of Africa.

In order to understand the significance of this research, and it is indeed very significant, you need to have a detailed history of archaeological research in Europe, the Near East, and Africa. But since there isn’t time for that I’ll give you the following bullet points. Each of these bullet points reflects the general understanding of prehistory at a certain point in time, in order from oldest to newest.

This shows the Victoria West technique, used during the Fauersmith though this particular rock may be later). See the extra small flaking along one part of the rock? That was done to prepare the platform for the controlled detachment of a flake.

In the 70s and before, we thought this:

As humans evolved they went through stages where the morphology would change, usually involving an enlargement of the brain, along with the behavior, usually indicated by changes in stone tools. So, Homo erectus used acheulean tools (hand axes), Neanderthals used Mousterian tools (Levallois technology) with prepared platforms, and modern humans (“Cro Magnon”) used upper paleolithic technology and they had nice art too. The transition from Neanderthal times to Modern Human times happened 40,000 years ago.

The levallois technique. this involved shaping a rock to look like a turtle. Then, you shape one end of the turtle to look like the old fashioned hat of a French policeman. Then you hit the policeman on the hat just right, and a perfect flake comes off. In Africa, this was usually used to make blades and triangular points, but sometimes ovals.
In the 80s we realized that there was no association whatsoever between the various “industries” and the various “hominids” mainly because a lot of research in the Middle East kept finding Neanderthals and Modern Humans randomly associated with various technologies. This caused a disturbance in the force, so the whole idea of linking morphology (i.e, different species or subspecies) with different levels or modes of technological activity was tossed out the window.

Also in the 1980s and continuing into the early 1990s, African archaeologists realized something. Well, they realized two things. Most of us realized that at a certain point of time, which Sally McBreardy and Allison Brooks estimated to be about 250,000 years ago or a bit earlier, a “middle paleolithic” world with a lot of handaxes and some other bifaces (Sangoan-Lupemban technologies, that sort of thing) gave way to a “Middle Stone Age” technology. This MSA technology was essentially the same as but somewhat more advanced than what the Europeans called “Middle Plaeolithic” based on the Levallois technique, a prepared platform technology.

Eventually, very advanced technologies and very advanced modes of thinking, such as exemplified by this possible calendar object from the Semliki Valley in the Congo, emerged.
Notice that I keep mentioning that term … prepared platform technology. Put a pin in that.

The second thing we all knew about but not every body liked was an idea by Peter Beaumont, which is that a certain technology had emerged earlier than the Acheulean-MSA transition of 250K, which was called Fauersmith. This was a … wait for it … prepared platform technology of sorts.

Classically, the handaxe based technology of the early stone age was replaced with the prepared platform technology. This meant throwing the handaxes one last time and moving on to blades and points made with the levallois technique. But in the Fauersmith, an industry found mainly in the Cape Province of South Africa and nearby areas (I think I’ve seen it in Namibia), uses … wait for it … prepared platform technology to make handaxes! This industry is thought to be just older than the MSA, so just older than 250K, going back maybe to 350K, or maybe 400K or even 500K, no one is sure.

The Africanists also realized that the Europeans were pretty messed up in their thinking. The species/subspecies link to technology never went away in Africa. While such a thing is never expected to be perfect, it seemed to hold there. The reason the Europeans were confused is this: When it comes to new species and new technologies, Africa is the donor and Eurasia the occasional recipient.

I liken it to figuring out the chronology and technology of trade beads, those little glass beads, still in use, that were carried by Dutch and English (and other) ships around the world mainly in the early 17th century, to trade with the locals and buy things like, say, Manhattan Island. If you look at the trade beads found here and there on colonial sites around the world, and I’ve personally done this, you can figure out a chronology of style and design of those beads that we assume reflects realty in the two or three places they were consistently made. But only by going to the factory neighborhoods in the Netherlands and Italy, and South Asia, can you actually figure out what was going on.

Putting it another way, trying to describe human evolution, substantively, by observing only Europe and West Asia and ignoring Africa is like, oh hell, I don’t know what the heck, why would you ever do that?

Anyway, here’s what many of us have been thinking all along, following the insights of folks like Peter Beaumont and Alison Brooks. Once upon a time there were these Homo erectus doods, and they have some moderate game in the brain department but were definitely not humans. They may have lacked some serious human mind tricks, though they were capable of making and using fire, and their handaxes were very nice, when they wanted them to be. They were also very tough and strong and probably somewhat dangerous. Oddly, the most common cause of death, when we can estimate cause of death, is that they ate something that killed them. So, there is some kind of deficit or something behind that.

Then, some time after about a half million years ago, a subset of these guys, and I know where they lived because I have sat on the exact rock chairs they themselves sat on while making their tools, added something to their hand ax technology. They had probably added other things to their culture, and/or their brains, and this hand ax technology thing merely reflected this, but it also opened the opportunity for developing this technology further, and that may have been actually contributory to the subsequent evolutionary process. Anyway, they added this thing where instead of just whacking a flake off a big rock, with the intention of then flaking that big flake into a handaxe, they would make a few smaller specially and carefully done flakes on the big rock, literally a giant piece of bedrock in some cases, that made the prot-handaxe flake they were about to produce more predictable (and, actually, larger in many cases, I think).

The prepared platform. It made making hand axes better. But, taken to the next step, which seems to have happened in this region probably before the Great Transition in 250K, it actually allowed the production of stone tool doohickies never before seen, never before possible. this eventually developed into the full on prepared platform technique that eventually became common all across Africa, Europe and West Asia.

Now, let me tell you a little story you won’t hear, likely, from somewhere else. I was once visiting my friend Peter Beaumont, and he showed me a skull, that was unfortunately unprovenienced, i.e., no one could be sure of where it came from, that looks a lot like the Jebe Irhoud skull and others of that general form and age range. He did have it dated using a technique that, without knowing more about the context of the skull (it has been collected in antiquity by a farmer, supposedly, in the region) could not be fully reliable, but the date was somewhere between 300K and 400K, closer to the latter, if I recall correctly.

For completeness, this is a modern South African cell phone tower.
Here’s the thing. Assume for a minute, and this is a major oversimplification but I’ll defend it if necessary, that there is some sort of reasonable association between species or subspecies and technology. I’ve already described, just now, how that is messy. The late Homo erectus of the Cape, if I’ve got my story right, were using MSA technology before they were “early modern humans” for example. But that is expected. Just assume that there is a general correlation, for the purpose of a though experiment.

Now, go out in that thought experiment landscape and imagine looking for both artifacts and diagnostic skull bits, so you can put the story together of a few different hominins over time, one evolving into the other, and their material culture, especially their stone tool technology.

You will figure out the boundaries in time and space of the technologies long before you verify the species or subspecies by the remains of their actual heads. the reason for that should be obvious, but if it isn’t, just go around the city and look at all the litter you find. Look carefully at all the litter. Cal me as soon as one of the pieces of litter is a human head. Actually, call 911 first, then me.

This new find is a head butting, perhaps, against the early time range for this species, previously expected from the Fauersmith theory.

I fully expect the key points in the article to be ignored and for Sub Saharan Africa to be broken off from the rest of Africa so that this find can be European/West Asian in stead of Africa, but to address that I’ll quickly tell you this; The Sahara may not have even existed then, so there may not have been a Sub Saharan Africa. Just an Africa. Where modern humans arose.

Odd Ancient South African Human “Ancestor” Is Young

You’ve heard of Homo naledi, the strange “human ancestor” (really, a cousin) found a while back in South Africa. There were many skeletal remains in a cave, in the kind of shape you’d expect if they had crawled into the cave and died there, not much disturbed. They look enough like other members of our genus, Homo, to be called Homo, but if we assume that increase in brain size is the hallmark of our species, they seem to be an early grade.

Over the last ten years, we have come to appreciate the fact that our genus may have differentiated into multiple species that did not have a large brain after all, and Homo naledi is one of the reasons we think that. And, just as the “Hobbit” of Indonesia (flores) has recently been re-dated to be a bit older than people thought, Homo naledi is now dated to be a bit later than people may have thought.

Schematic of the Rising Star cave system. Picture: Marina Elliott/Wits University
Schematic of the Rising Star cave system. Picture: Marina Elliott/Wits University

For me, this is an “I told you so” moment. First, I understand, as do most of my colleagues (but not all), that a regular change over time in a trait in one lineage does not magically cause a parallel change in another lineage (though the co-evolution of a single trait in a similar direction along parallel lineages is certainly possible.) So, there was no reason to require that all later period hominins be like all other later period hominins in those later-emerging traits. Also, since no one has ever adequately explained what the heck our big brains are for, I don’t subscribe to the presumption that all evolution will always evolve the big brain just because our own big brains insist that they are really cool. So, a late small brained hominin in our genus but existing long after the split with us is actually somewhat expected.

Then, there is my sense of age based on the things I’ve seen in the area’s caves.

Geologist Dr Hannah Hilbert-Wolf studying difficult to reach flowstones in a small side passage in the Dinaledi Chamber. Picture: Wits University
Geologist Dr Hannah Hilbert-Wolf studying difficult to reach flowstones in a small side passage in the Dinaledi Chamber. Picture: Wits University
Some time ago, Lee Berger took me around some of the cave he had poking around in (long before this hominin was discovered) and showed me several animals that had crawled into the caves, probably looking for water during an arid period (this is already a fairly dry area). They had died in place and become mummified. In other caves, I’ve seen similar things, like a troop of baboons that somehow got into a cave with no known entrance and died, as well as bats that died in situ and mummified against the rock they died on.

On another occasion, Ron Clarke, another anthropologist working in the area, showed me the famous “Little Foot” which is a fossil that represents that mummy-to-stone transition, while mostly sitting on the surface of the floor(ish) of a very deep and inaccessible cave. Meanwhile, I’d been working with my friend and colleague Francis Thackeray, and he demonstrated to me how many of the diverse bits and pieces we find of australopithecines are actually probably part of individual skeletons, but discovered and excavated at very different times. These are creatures that got in the cave somehow, and were only somewhat disarticulated after death.

The whole “crawled into the cave” mode of entering the fossil record, and its presumed variant, “fell to one’s death in the cave” is different from the previously presumed process of “leopard kills you, drags you onto a tree branch hanging over a cave entrance and your bones fall into the cave” means of becoming a fossil. It is of course possible, even likely, that both of these processes occurred at various times and places.

Homo naledi, according to Lee Berger, may represent a third way of getting into one of these famous caves. He suggests that the hominins themselves dragged the dead bodies of each other into the caves, as a form of treatment of the dead. That is a spectacularly controversial claim, of course, since with a small brain how can you have a god, and without a god, how can you have ritual or burial? Of course, elephants treat their dead specially sometimes, and their brain is right where it is supposed to be on the famous mouse-to-elephant curve of brain size. And, I’d bet a dozen donuts that even though Homo naledi has a small brain compared to, say, yours or mine, it is probably a good measure above that comparative curve. It was a primate, after all.

left to right: Marina Elliott, Maropeng Ramalepa and Mpume Hlophe. Picture: Wits University/Wayne Crichton
left to right: Marina Elliott, Maropeng Ramalepa and Mpume Hlophe. Picture: Wits University/Wayne Crichton
But I digress in several directions, lets get to the point. The site of Rising Star Cave, South Africa, where Homo naledi was discovered, is now dated. These things are always subject to revision and updating, but for now, it seems like we have a pretty good estimate of the age of this incredible site.

The site dates to some time between about 414,000 years ago and 236,000 years ago. That means that the site overlaps with the approximate age of the earliest, probably, modern humans. Here are the details from the abstract of the paper, published this morning:

New ages for flowstone, sediments and fossil bones from the Dinaledi Chamber are presented. We combined optically stimulated luminescence dating of sediments with U-Th and palaeomagnetic analyses of flowstones to establish that all sediments containing Homo naledi fossils can be allocated to a single stratigraphic entity (sub-unit 3b), interpreted to be deposited between 236 ka and 414 ka. This result has been confirmed independently by dating three H. naledi teeth with combined U-series and electron spin resonance (US-ESR) dating. Two dating scenarios for the fossils were tested by varying the assumed levels of 222Rn loss in the encasing sediments: a maximum age scenario provides an average age for the two least altered fossil teeth of 253 +82/–70 ka, whilst a minimum age scenario yields an average age of 200 +70/–61 ka. We consider the maximum age scenario to more closely reflect conditions in the cave, and therefore, the true age of the fossils. By combining the US-ESR maximum age estimate obtained from the teeth, with the U-Th age for the oldest flowstone overlying Homo naledi fossils, we have constrained the depositional age of Homo naledi to a period between 236 ka and 335 ka. These age results demonstrate that a morphologically primitive hominin, Homo naledi, survived into the later parts of the Pleistocene in Africa, and indicate a much younger age for the Homo naledi fossils than have previously been hypothesized based on their morphology.

"Neo" skull of Homo naledi from the Lesedi Chamber. Photo credit: Wits University/John Hawks
“Neo” skull of Homo naledi from the Lesedi Chamber. Photo credit: Wits University/John Hawks
In addition to this date, it is reported that there are more fossil remains, from another cave called Lesedi Chamber. Here is the paper for that, which reports “… Further exploration led to the discovery of hominin material, now comprising 131 hominin specimens, within a second chamber, the Lesedi Chamber. The Lesedi Chamber is far separated from the Dinaledi Chamber within the Rising Star cave system, and represents a second depositional context for hominin remains. In each of three collection areas within the Lesedi Chamber, diagnostic skeletal material allows a clear attribution to H. naledi. Both adult and immature material is present. The hominin remains represent at least three individuals based upon duplication of elements, but more individuals are likely present based upon the spatial context. The most significant specimen is the near-complete cranium of a large individual, designated LES1, with an endocranial volume of approximately 610 ml and associated postcranial remains. The Lesedi Chamber skeletal sample extends our knowledge of the morphology and variation of H. naledi, and evidence of H. naledi from both recovery localities shows a consistent pattern of differentiation from other hominin species.”

Since both articles are OpenAccess, you can see them for yourself. Kudos to the authors for publishing in an OpenAccess journal.

And now, back to my original digression. One gets a sense of how landscapes and land forms develop, and while this can be misleading, it is not entirely absurd to postulate rough comparative ages for things you can see based on other things you’ve seen. I had assumed from the way they were described originally that the Rising Star hominins would not be millions of years old. Even though Bigfoot (found by Clarke) was millions of years old and essentially on the surface (of a deeply buried unfilled chamber) I guessed that over a million-year time scale, the Rising Star material would either become diagenetically inviable as fossils or buried in sediment, or both. But over hundreds of thousands of years? That was plausible to me. In fact, I figured the remains to possibly have been even younger, and if a date half the age as suggested was calculated, I would not have been surprised.

The evolution of our thinking about human evolution went through a period when we threw out all of our old conceptions about a gradual ape to human process, replacing that with a linear evolutionary pattern with things happening in what was then a surprising order, with many human traits emerging one at a time long before brains got big. There was some diversity observed then, but the next phase of our thinking involved understanding a dramatic diverstiy of pre Homo (the genus) life forms followed by the essential erasure of variation with the rise of Homo erectus and the like. Over the last decade and a half, we are now realizing that while the later members of our genus probably did cause, or at least, were associated with, a general decrease in that early diversity, later diversity arose anyway, and there were more different kinds of hominids, very different in some cases, late into our history. Word on the street is that we can expect to learn about even more diversity in coming years.


Paul HGM Dirks, Eric M Roberts, Hannah Hilbert-Wolf, Jan D Kramers, John Hawks, Anthony Dosseto, Mathieu Duval, Marina Elliott, Mary Evans, Rainer Grün, John Hellstrom, Andy IR Herries, Renaud Joannes-Boyau, Tebogo V Makhubela, Christa J Placzek, Jessie Robbins, Carl Spandler, Jelle Wiersma, Jon Woodhead, Lee R Berger. 2017. The age of Homo naledi and associated sediments in the Rising Star Cave, South Africa. May 2017. eLife.

Related books:

Almost Human: The Astonishing Tale of Homo naledi and the Discovery That Changed Our Human Story

Field Guide to the Cradle of Humankind: Sterkfontein, Swartkrans, Kromdraai & Environs World Heritage Site

From Apes to Angels: Essays in Anthropology in Honor of Phillip V. Tobias

Darwin’s Unfinished Symphony

Darwin’s Unfinished Symphony: How Culture Made the Human Mind is a new book on cultural evolution in humans from a biological perspective.

This is an interesting book and a good book, and I recommend it, but I need to add a strong caveat. The author could have made a more compelling argument had he more carefully studied and used some of the prior work that makes a similar argument. He strangely cites Terry Deacon in two places (once as a psychologist, incorrectly) for work Deacon has done, but seems to ignore Deacon’s key thesis, which is pretty much the same as Laland’s key thesis. (See: Incomplete Nature: How Mind Emerged from Matter.) There are other examples of prior work not known about, apparently, or incorporated. But, nonetheless, Laland does present a reasonable stab at how to think about human culture in relationship to evolution and an interesting “theory” of how it all came to be, even if it is presented as more original than it actually is.

From the publisher’s description:

Humans possess an extraordinary capacity for cultural production, from the arts and language to science and technology. How did the human mind–and the uniquely human ability to devise and transmit culture–evolve from its roots in animal behavior? Darwin’s Unfinished Symphony presents a captivating new theory of human cognitive evolution. This compelling and accessible book reveals how culture is not just the magnificent end product of an evolutionary process that produced a species unlike all others–it is also the key driving force behind that process.

Kevin Laland shows how the learned and socially transmitted activities of our ancestors shaped our intellects through accelerating cycles of evolutionary feedback. The truly unique characteristics of our species–such as our intelligence, language, teaching, and cooperation–are not adaptive responses to predators, disease, or other external conditions. Rather, humans are creatures of their own making. Drawing on his own groundbreaking research, and bringing it to life with vivid natural history, Laland explains how animals imitate, innovate, and have remarkable traditions of their own. He traces our rise from scavenger apes in prehistory to modern humans able to design iPhones, dance the tango, and send astronauts into space.

This book tells the story of the painstaking fieldwork, the key experiments, the false leads, and the stunning scientific breakthroughs that led to this new understanding of how culture transformed human evolution. It is the story of how Darwin’s intellectual descendants picked up where he left off and took up the challenge of providing a scientific account of the evolution of the human mind.

The Great Human Race: How to survive

The Great Human Race is a new production of National Geographic, in three parts. I recently viewed the first episode, “Dawn” which comes with this description:

All people can trace their roots to the savanna of East Africa, the home of one of the first members of the human species — Homo habilis. Archaeologist Bill Schindler and survival instructor Cat Bigney face what early man did as they work together to survive in the wild savanna just as these primitive people did 2.6 million years ago — without any weapons or fire. But they soon find that living like our ancestors is harder than they expected.

Great Human Race premieres Monday, February 1, at 10/9c on National Geographic Channel.

Photo at the top of the post: NG Studios

NGS has asked me to participate in a roundtable (here is the link to the roundtable) focusing on this documentary, specifically addressing this question:


Do you think that experts today can accurately replicate the challenges that Homo habilis faced thousands of years ago? And do you think that experts today could survive and thrive as Homo habilis did?

This is very much my area, and I’m glad to contribute to the discussion. The short answer is, of course, no, this is too hard. But, we can try and in so doing, we can develop some interesting thinking about early human evolution.

My contribution to the conversation centers on two rules of being a human hunter gatherer. Homo habilis was not, of course, a human, but we assume that this early hominin had some incipient human traits, further developed with early Homo erectus/ergaster. The two rules of being a human hunter gatherer refer to important aspects of living off the land that my research indicates apply to modern humans living without agriculture or animal husbandry as a source of food. I don’t know if these rules applied to earlier hominins or not … that is the $64,000 dollar question.

Rule 1: If you don’t know where it is, you are not likely to find it.

Much of the story in the first episode of The Great Human Race has to do with the two scantily clad protagonists, a professional survivalist of sorts and an “experimental archaeology” expert, set lose in the African Savanna to see what would happen, searching for various resources. I won’t give you a spoiler, but the episode ends with their discovery of one of the most important resources they need to survive, with that discovery realized in a very spectacular way.

I spent a lot of time in the 1980s and early 1990s living with, and studying the foraging patterns of, the Efe Pygmy foragers of the Ituri Forest, Zaire (now Congo). One of the things I discovered and documented is the simple fact that most of the resources they use are not really found by them, as though they had no idea where they might be. They already know where most of the stuff they can eat either will be, or are likely to be.

Bot men and women gather plant resources, but this is more of a woman’s job. In most cases, the more important plant resources are well known fruiting trees or concentrations of trees, or patches of wild yams that are frequently exploited. Women catch fish in streams that they have fished repeatedly before. This involves damming the stream at two points and removing the water from between the dams so the fish are easy to harvest.

Men seasonally hunt honey, and much of the honey is taken from trees they have exploited in the past, and check on a regular basis to see if the bees have settled in that cavity again. They do occasionally cut down a honey tree, but this is fairly rare (it is very hard work).

Even hunting, which one might assume is somewhat random, is done with a great deal of expectation based on knowledge. One type of hunting (not the most revered but among the most predictable) is to take porcupines or other small mammals from cavernous areas beneath rock piles that are found here and there across the landscape. If you find a rock pile and try to get at the animals hiding in it, even with the use of dogs, the animals can easily escape as they have many hidden exists. But if you return to the same rock pile repeatedly, you know where many of these escape routes are and can block them with wood or stone. A repeatedly used rock pile can be exploited with a high degree of confidence in success.

One of the most productive methods of hunting is the ambush. A well known tree that produces a fruit eaten by small ground mammals such as duikers is identified as currently producing the bait. A nearby tree which is climbable is used as a hide, where the Efe man waits for his prey, shooting it from the tree. The Efe almost always camp in locations that were previously used as camps, so at any given location where they are living, any of the men can easily point out the location of excellent ambush sites, rock piles, and nearby potential honey spots, and the women, and some of the men, can easily point out the locations of nearby fruit trees or yam patches.

There is uncertainty as to what resource will pay off, and not every resource is so easily predicted, but most of the wild foods the Efe gather and hunt are exploitable because of this knowledge.

The information is probably shared among people in a group, but remarkably little conversation centers on this topic. You don’t hear Efe talking about the location of this or that resource more than you hear, say, Americans talking about the locations of this or that grocery story. Certainly, such things are part of the normal conversation but do not make up a large percentage of it.

Rule 2: If you are doing it right, the use of a given instance of a resource can increase its future return.

This is probably a more important finding than that related to the first rule, and is rather counterintuitive. If the Efe use a resource, they will quickly use it up. This is one of the main reasons they move frequently from camp to camp over the year. But, the value of that resource, both the likelihood that it will produce something, and the abundance it produces, is enhanced by their very use of it.

I’ve already implied a couple of examples. If you block off a few exit ways on a rock pile, you don’t unblock them when you are done. Those escape routes may remain blocked between uses. If you add to your ambush trees a blind to sit on (usually just a few sticks tied on here and there) or modify the tree to make it easier to climb, these modifications may make the use of that ambush spot easier in the future, allowing you to climb and sit in the tree more quickly, more quietly, and more comfortably. Efe will also remove branches that interfere with their view and their shot.

Often, after an Efe man has finished taking the honey and comb out of a bee nest way up in some tree, he will spend a few more minutes making the cavity the bees had nested in larger. This may increase the amount of honey that can be fit into that cavity the next honey season.

When Efe women harvest yams, they tend to keep the “head” of the yam, attached to the above ground vine, intact, and rebury it. The space where they took the yam out will then be filled, with a little luck, with more yam months later.

As the Efe walk along the trails they habitually use to get around in the forest, they maintain the trails to keep them open and passable. it takes an Efe twice as long to traverse a given distance of forest without a trail as with a trail. This is a huge long term enhancement in the return of foraging.

As the Efe walk along a trail, they often grab up fruits from trees along the way. They eat the fruit as they walk, or stop at a resting place and eat it there. I documented five species of fruit tree where the Efe spit out or otherwise discard the seed of the fruit. This process of dispersal, well known to plant ecologists, enhances the number of those fruit trees along these trails, roughly doubling the abundance of these seasonally consumed fruits.

And there’s more, I won’t bore you with now. Much of the energy the Efe put into foraging enhances future return, including the development and maintenance of the basic knowledge of where various resources are.

There is some evidence that chimps do something like this as well. Chimps are probably primary dispersers of some of the fuits they exploit, almost certainly enhancing the abundance of that type of tree or plant. Where chimps use nutting stones (this is rare, but there are some groups that do this), they seem to keep track of the where the stones were left, so finding this rare object is much more efficient.

Given that chimps use prior knowledge and enhancement a little, and human foragers are capable of using these two “rules” a lot, I would assume that some of this would have been going on with Homo habilis.

I should mention that the observations I’ve made with the Efe have since been made among other groups of foragers. This seems to be a general pattern among African tropical and subtropical foragers, and possibly beyond. If you don’t already know where something is, you are not likely to find it. And, once a resource is exploited, foragers are often likely to enhance its future value. The emergence of those two features of modern human foraging must have been part of the hominin evolutionary story.

How Dogs Won The World

Years ago I proposed a theory (not anywhere in print, just in seminars and talks) that went roughly like this. Humans hunt. Dogs hunt. Prey animals get hunted. Each species (or set of species) has a number of characteristics such as the ability to stalk, track, kill, run away, form herds, etc. Now imagine a landscape with humans, wolves, and game animals all carrying out these behaviors, facilitated with various physical traits. Then, go back to the drawing board and redesign the system.

The hunting abilities of humans and dogs, the tendency of game animals to herd up or take other actions to avoid predation, etc., if disassembled and reassembled with the same actors playing somewhat different roles, give you a sheep herder, a protecting breed of dogs (like the Great Pyrenees or other mastiff type breeds), a herding dog (like a border collie) and a bunch of sheep, cattle, or goats.

Even human hunting with dogs (not herding domesticated animals) involves a reorganization of tasks and abilities, all present in non-dog-owning human ancestors and wolves (dog ancestors), but where the game are, as far as we know, unchanged. Human hunters documented in the ethnographic record, all around the world, had or have dogs, and those dogs are essential for many hunting types. The Efe Pygmies, with whom I lived in the Congo for a time, use dogs in their group hunting, where they spook animals into view for killing by archers, or drive them into nets that slow the game down long enough to be killed. The Efe actually get a lot of their game by ambush hunting, where a solitary man waits in a tree for a game animal to visit a nearby food source. He shoots the animal from the tree with an arrow. But, even then, the dog plays a role, because the wounded animal runs away. The trick to successful ambush hunting is to do it fairly near camp so you can call for help when an animal is wounded. Someone sends out a dog, and the dog runs the animal to ground. And so forth.

Scientist and science writer Pat Shipman has proposed another important element that addresses a key question in human evolution. Neanderthals, who were pretty much human like we are in most respect, and our own subspecies (or species, of you like) coexisted, but the Neanderthals were probably better adapted to the cooler European and West Asian environment they lived in. But, humans outcompeted them, or at least, replaced them, in this region very quickly once they arrived. Shipman suggests that it was the emerging dog-human association, with humans domesticating wolves, that allowed this to work. Most remarkably, and either very insightfully or totally fancifully (depending on where the data eventually lead), Shipman suggests that is was the unique human ability to communicate with their gaze that allowed this to happen, or at least, facilitated the human-dog relationship to make it really work. We don’t know if Neanderthals had this ability or not, but humans do and are unique among primates. We have whites around our Irises, which allow others to see what we are looking at, looking for, and looking like. We can and do communicate quite effectively, and by the way generally viscerally and honestly, with our glance. This, Shipman proposes, could have been the key bit of glue (or lubricant?) that made the human-dog cooperation happen, or at least, rise to a remarkable level.

The Invaders: How humans and their dogs drove Neanderthals to extinction, by Pat Shipman, outlines this theory. But that is only part of this new book. Shipman also provides a totally up to date and extremely readable, and enjoyable, overview of Neanderthal and contemporary modern human evolution. Shipman incorporates the vast evidence from archaeology, physical anthropology, and genetics to do so, and her book may be the best current source for all of this.

This is a fantastic book, and I highly recommend it. Shipman also wrote “The Animal Connection,” “The Evolution of Racism,” “The Wisdom of the Bones: In Search of Human Origins,” and several other excellent books on human evolution and other topics. Shipman, prior to becoming mainly a science writer, pioneered work in the science of Taphonomy, developing methods for analyzing marks on bones recovered from archaeological and paleontologic sites, such as those marks that may have been left by early hominins using stone tools to butcher animals.

Seriously, go read The Invaders: How humans and their dogs drove Neanderthals to extinction.

Tales of the Ex-Apes

Jonathan Marks’ new book is called “Tales of the Ex-Apes: How We Think about Human Evolution

I’ve got to tell you that when I first saw the title of this book, the letters played in my head a bit. Tails of the Ex-Apes. That would be funny because apes don’t have tails. Or Tales of the Exapes. Pronounced as you wish. Perhaps in an Aztec accent.

Anyway…

Staley_2009_author_lJon Marks is a colleague and a friend from way back. He is a biological anthropologist who has engaged in critical study of central biological themes, such as genetics, and he’s said a few things about race. He wears black, often does not shave, and has probably been a member of the Communist Party, or at least, taught a class or two on Marxist Theory. So, a book by Marks on “how we think about human evolution” (the subtitle) is not going to be about human evolution, but how we frame questions about human evolution, and how the process of unraveling answers to these questions revel our own biases. Dialectical stuff. Like that.

In the book Jon says interesting things about basic anthropological theory, thought, and key touchstone figures and topics like Darwin and kinship. On the more biological side of things, species, adaptations, gene trees, and phylogeny. The destructive core of the book is an anti-reductionist critique of evolutionary theory and the constructive core of the book is an bio-cultural argument as it applies to doing anthropology, as well as how it applies to the human (or just prehuman?) transformation to a self considering sort of sentient being that bothers to write books about the process of asking questions about itself. Humans are a product of lived experience, but not just that. Humanness is the product of the sum of human’s cultural history. And, actually, science, which is an important human thing, does not escape that framework, something I probably agree with (^^see the subtitle of my blog^^). Marks writes,

… we see the human species culturally. Science is a process of understanding, and we understand things culturally. We hope that we can observe and transcend the cultural biases of our predecessors, but there is no non-cultural knowledge. As a graphic example, consider the plaque that was attached to Pioneer 10 … Why was NASA sending pornography into outer space? … Because they wanted to depict the man and woman in a cultureless, natural state. But surely the shaves, haircuts, and bikini waxes are cultural! As are the gendered postures, with only the man looking you straight in the eye. In a baboon, that would be a threat display; let’s hope the aliens … aren’t like baboons.

And so on. Like that. Great book.

If you are teaching a course in human evolution, you might seriously consider using this as a second reading because of the critical treatment of material surely left unexamined by your textbook. Also, it would give the students a fairer sense of what they are in for if they chose Anthropology as a major, for better or worse. This is not introductory material, but the prose would work for any college student. Also, the text is well footnoted.

The book will be out any day now, scheduled for September. Available in various formats, very much worth the read.

The significance of the new East Asian fossil human Penghu 1

A new early human fossil has been reported, recovered from the seabed near Taiwan. We are calling it Penghu 1.

Simply put, it is the lower right jaw of a hominid (hominine) that most resembles either a form of Homo erectus or Archaic Homo sapiens (kin to, but not, Neanderthal). Teeth are fairly useful for categorizing hominids into groups that can be thought of as species. This hominid does not look like modern humans (teeth are way too big and the enamel is not right). It does not look like African Homo ergaster or Asian Homo erectus. It does not look like Neanderthal or so called Denisovan. It looks most like Hexian, a middle pleistocene hominid (about a half million years old) from China, but not exactly. But close. Hexian, for it’s part, looks like earlier Homo erectus but changed over time to be distinctly different from other contemporary (late) Homo erectus from East Asia.

I’ll provide more information about the fossil below, but since the paper that reports it is available on line you might as well go read the original. Rather, I’d like to say a couple of things about the possible significance of this find.

First, this is probably a new species, though it could end up getting lumped with Hexian. But, the new fossil probably dates to the last interglacial (120,000 years go) or later. I’m guessing later if its presence on the sea floor indicates that the original possessor of the mandible lived during times of lower sea level. (I suppose this could be an individual that died and floated down a river. Or fell out of a boat!?!?!?)

Let’s assume for a moment that Penghu 1 is a new species, in the sense that we see Neanderthals, Denisovans, and various variants of Homo erectus or Archaic homo as different species (we’ll put aside species-population differences and arguments for now). If so there is one obvious very significant (provisional) conclusion that could be advanced, and a second less obvious (and more provissional).

The obvious significance is that Penghu is yet another indicator that multiple different hominids lived on the Earth at the same time after the rise of Homo erectus. We see lots of different hominids, mainly called Australopithecus, in Africa prior to about two million years ago, which is interesting but also known for some time now. But for a long time it looked like there was not too much diversity in the fossil record after that, though we’ve always seen some. Over the last couple of decades, though, the evidence for Pleistocene diversity in Eurasia appears to have grown, with Homo floresiensis and Hexian in the east, Denisova Cave in the middle, and the hominid from the Republic of Georgia in the west. The idea of a high level of diversity is not new, but it is a relatively recent concept and is growing. (I’ll also mention that finding a new hominid on the sea floor underscores the problem we have that so many of the great places for early humans to live are inundated!)

The less obvious and much more conjectural significance is in the shift of diversity from one region of the world to another. Prior to about 2.0 million years go, we see great diversity in hominids in Africa (where, for the most part, most of the hominids lived). Over time, African diversity dwindles as modern humans, or a hominid just precedent to modern humans, seems to have more or less taken over and replaced their contemporaries. Archaic hominids, however, which had already spread into Eurasia, continued the diversification earlier hominids had achieved, and this diversity was manifest in the absence of those pesky moderns.

Putting this another way, one could say that hominids, including pre- and post-Homo forms, have as one of their characteristics a propensity to diversity. This is true of many (but not all) primates. It may have to do with ecological and social/cultural characteristics of the various species, or perhaps basic demography. Adherence to ecological zones that are patchy and spread apart would encourage more speciation than might occur if populations were more connected or continuous. Related (or alternatively, depending) great increases and decreases of population size, causing separation of subgroups, might enhance this. At the same time, evolutionary stasis is repressed; separate groups change fast enough to be noted by us on time scales of several thousand years.

In contrast, modern or near-modern humans seem not to have had this propensity.

The most obvious explanation for this difference is, it seems to me, the degree of cultural buffering found in modern humans being much higher than in these other hominids.

OK, enough of the wild speculation. Here is the abstract from the paper:

Recent studies of an increasing number of hominin fossils highlight regional and chronological diversities of archaic Homo in the Pleistocene of eastern Asia. However, such a realization is still based on limited geographical occurrences mainly from Indonesia, China and Russian Altai. Here we describe a newly discovered archaic Homo mandible from Taiwan (Penghu 1), which further increases the diversity of Pleistocene Asian hominins. Penghu 1 revealed an unexpectedly late survival (younger than 450 but most likely 190–10 thousand years ago) of robust, apparently primitive dentognathic morphology in the periphery of the continent, which is unknown among the penecontemporaneous fossil records from other regions of Asia except for the mid-Middle Pleistocene Homo from Hexian, Eastern China. Such patterns of geographic trait distribution cannot be simply explained by clinal geographic variation of Homo erectus between northern China and Java, and suggests survival of multiple evolutionary lineages among archaic hominins before the arrival of modern humans in the region.

The citation and link:

Chun-Hsiang Chang, Yousuke Kaifu, Masanaru Takai, Reiko T. Kono, Rainer Grün, Shuji Matsu’ura, Les Kinsley & Liang-Kong Lin. The first archaic Homo from Taiwan. Nature Communications. 27 January 2015.

The location:
Penghu_1_Hominid_Location

And above the post is a picture of the fossil.

How to find a Leprechaun

Nature editor and author Henry Gee has produced his Christmas list in which he describes his three wishes as an editor at a scientific journal; he enumerates the scientific discoveries that sit at the top of his professional “bucket list.”

Henry Gee. Not a Leprechaun.
Henry Gee. Not a Leprechaun.
I started to write a comment on Henry’s blog post, here, but it turned into a blog post of my own, here:

Henry: As you know, I address in a fictional context in “Search for Sungudogo” (now only 99 cents on Amazon) all three of your wishes, the discovery of life elsewhere in the universe, the discovery of intelligent life somewhere, and the documentation of non-human hominids in recent times (including the present) like, but later than, the “Hobbit” at Flores. (Drop me a line for a review copy.) In the revised version of the novella I also explain the origin of Penn and Teller. But I digress.

The chance of the existence of Homo notspaiens at present must be zero, unfortunately. But I do like the idea of proto-historical or historical cases. “Like” as in how a TV detective “likes” a particular suspect for a particular crime. Maybe it is just a hunch. A re-examination of all those cases in the sepia literature of little people or not-quite-humans thought to be imagination, serious confusion, or out and out racism may be necessary.

I’d like to put a finer point on the prediction though. The hominid needs to have existed after some key point in time (which may be hard to identify on the ground but that could be fairly easily defined as an archaeological or historical transition). For example, post first writing or post settled horticulture. Flores already fits the obvious next oldest criterion of post Last Glacial Maximum (LGM). Also, and this is not a requirement but it would be way cool, I would like them to have existed at the same time as and in the same region as the Wrangle Island Mammoths because then tiny people-like creatures could have hunted, or ridden, or otherwise lived among, tiny furry elephants.

Also, I’ll offer a prediction of where the hominid would have lived. It is most likely to be in an area where the landscape has two distinct habitats that are long term and well defined. One is a habitat likely to be inhabited long term by regular humans and the other where regular humans are likely to forage or visit only now and then, but where this second, marginal, habitat is livable. Also, it is more likely at the outer edge of post-LGM expansion, and in a region where human population would not have been dense prior to the great Exchange of Horticultural Products that began in the 15th century. (In fact if I were to pick the most likely local date formula for the extinction of Homo notsapiens globally, if there were a bunch of them, it would be the introduction of yams, manioc, maize, taro, or other staple plant brought in from the other side of the planet to grow locally.) This means the Flores hominid may have chipped its last rock when cassava or corn were first planted in the region, which would be very late and easily meet your criteria. I assume people are looking vigorously.

Yes, I just described Flores, but that’s the point. Those are the characteristics that allowed for the Indonesian Leprechaun. We might look at regions covered by the last glacial ice mass, regions far to the east of Africa, dense tropical rain forest, etc.

This also predicts that stories of “the little people” (or “the big people” depending) would be distributed more commonly in a certain region of the world’s map. Like this, maybe (and roughly):

Where to look for lepruchans or big foots.
Where to look for Leprechauns or Bigfoots.

I’ve ruled out the new world simply because. Bad reason, I know. It is entirely possible that the New World was thickly inhabited by Taltos and Leprechauns, the only really solid argument against that being a complete lack of evidence…

Catching Fire. The other one.

Catching Fire is apparently a very popular book and/or movie that everyone is very excited about. But Catching Fire: How Cooking Made Us Human is a different a book about some interesting research I was involved in about the origin of our genus, Homo.

You can pick up a copy of our paper on this page. We call it “The Cooking Hypothesis.” The basic idea can be summarized with these points:

1) Cooking food transformed human ecology. Many potential foods in the environment can’t be consumed by humans (or apes in general) without cooking. But adding cooking to our species-specific technology, we can access those foods effectively transforming our ecology to a much greater extent than the vast majority of evolutionary transitions, especially single-event transitions, have ever done. The total number of calories in the natural environment that become available to an ape that can cook goes up by orders of magnitude.

2) This increase in available calories left a biological signal that is very impressive. Two major changes happened in the hominid body (in early Homo erecuts/ergaster). One is an approximate doubling in body size from an earlier Australopithecine or “Early Homo” ancestor. The other is a reduction in tooth size. Less eating equipment with a body demanding so much more in energy to grow and maintain signals a fundamental change in the food supply. There may be more than one way this could have happened, but so far adding cooking to our technology seems to be the best explanation.

3) Related, this is when we see brain size, relative to body size and in absolute terms, increase. Neural tissue is picky, expensive, and costly. Having a significant increase in brain size may be related to the demands (on the brain) of adding cooking to our behavior in that the size increase is allowed by the extra energy. And, it may be related in that the larger brain may provide the capacity to have this behavior.

4) The actual act of cooking, as a technology, may or may not demand a larger brain. But the process of cooking almost certainly involves central place foraging (bringing all the food back to one place, much of the time, to cook it) and delayed consumption (as opposed to eating the food where you find it). The basic pattern for a chimpanzee-like ancestor is to eat the food where you find it. Bringing food into close proximity to other members of your group virtually guarantees direct competition for food, which makes getting to food to begin with a highly questionable thing to do. In order for cooking to work, the social interactions typical of an ape have to be modified significantly. Cooking demanded, facilitated, and made major changes in social structure “worth it” from the point of view of natural selection.

5) These changes in social structure are probably indicated as well by changes in stone tool technology. Early cookers also were early hand-ax makers, for example. Human ancestors went from making primarily expedient, one time use, very simple stone tools to making tools that required a great deal of investment in time and energy to learn the technology, get good at it, and even for the production of individual tools (including acquisition of better than average raw materials in many cases). Once the tools were made they seem to have been used, often, for long periods of time. It is hard to imagine a chimp-like creature carrying around a tool into which she invested time and energy without it being taken away. This is an important transformation.

6) Less visible but very likely is a change in social system which could be called the rise of proto marriage. Sexual arrangements of a human-like kind are very different than for chimp. The ability to allow others to possess food or invest in more sophisticated technologies may be parallel to the ability to have more or less exclusive sexual contracts among individuals. This is indicated independently in the fossil record by a large decrease in sexual dimorphism in body size. In polygynous species like chimps males are often much larger than females, and this seems to have been the case with pre-Homo erectus/ergaster ancestors. But at the same time the body size increase and tooth size decrease happen, we also see a reduction in sexual dimorphism in body size, strongly indicating a major change in social arrangements. The best two explanations for this may be a shift to a gibbon-like pattern of paired-off monogamous adults living more or less alone, or a human-like pattern of paired-off monogamous adults living in larger social groups.

It is an idea that would have caught on. It would have selected for more nuanced communication, and may thus have facilitated the origin of what we now know of as human language and symbolic processing.

So when you are eating your Thanksgiving dinner this year, most of which will be cooked, look around at the people at the table and, briefly, imagine them to be chimps. Then go back to your meal and try to put all those thoughts aside…