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Big Brains Require An Explanation, Part VI:
Why Learning Is Fundamental, Even For Australopithecines

Our Story So Far (abridged)

  • By 3.4 MYA, Australopithecus afarensis was most likely eating a paleo diet recognizable, edible, and nutritious to modern humans. (Yes, the “paleo diet” predates the Paleolithic age by at least 800,000 years!)
  • The only new item on the menu was large animal meat (including bone marrow), which was more calorie- and nutrient-dense than any other food available to A. afarensis—especially in the nutrients (e.g. animal fats, cholesterol) which make up the brain.
  • Therefore, the most parsimonious interpretation of the evidence is that the abilities to live outside the forest, and thereby to somehow procure meat from large animals, provided the selection pressure for larger brains during the middle and late Pliocene.
  • A. africanus was slightly larger-brained and more human-faced than A. afarensis, but the differences weren’t dramatic.

(This is Part VI of a multi-part series. Go back to Part I, Part II, Part III, Part IV, or Part V.)

And here’s our timeline again, because it helps to stay oriented:

Timeline of hominin evolution

Click the image for more information about the chart. Yes, 'heidelbergensis' is misspelled, and 'Fire' is early by a few hundred KYA, but it's a solid resource overall.


It Doesn’t Take Much Selection Pressure To Change A Genome (Given Enough Time)

When we’re talking about the selection pressure exerted by the adaptations our ancestors made to different dietary choices, it’s important to remember that it only takes a very small selective advantage to make an adaptation stick.

The path to fixation

Remember, these are based on the most pessimistic assumptions possible.

The math is complicated, and I don’t want to drag my readers through it—but even under the most pessimistic initial assumptions (Haldane 1957), the following rules of thumb hold:

  • A mutation that confers a 10% selective advantage on a single individual takes, on average, a couple hundred generations to become fixed (present in 100% of the population).
  • Even a mutation that confers a tiny 0.1% selective advantage takes only a few thousand generations to become fixed.
  • Therefore, a 10% selective advantage would have become fixed in just a few thousand years—a fraction of an instant in geological time.
  • Even a 0.1% selective advantage would have taken perhaps 50,000 years to reach fixation—still an instant in geological time, and well beyond the precision of our ability to date fossils from millions of years ago.

I’m using approximate figures because they depend very strongly on initial assumptions and the modeling method used…not to mention the idea of a precisely calculated figure for “selective advantage” is silly.

Why is this important? First, because we need to remember that we are thinking about long, long spans of time. All of what we blithely call “human history” (i.e. the history of agriculture, from the Sumerians to the present) spans less than 10,000 years, versus the millions of years we’ve covered so far!

Second, and most critically, it’s important because we don’t need to posit that australopithecines ate lots of meat in order for the ability and inclination to be selected for—and to reach fixation. Even if rich, fatty, calorie-dense meat (including marrow and brains) only provided 5% of the australopith diet—and 4.9% of that advantage was lost due to the extra effort and danger of getting the meat (it doesn’t matter if you’re better-fed if a lion eats you)—the remaining 0.1% advantage still would have reached fixation in perhaps 50,000 years.

In other words: the ability and inclination to eat meat when available might have been a tiny advantage for an individual australopith…but given hundreds of thousands of years, that tiny advantage is more than sufficient to explain the existence and spread of meat-eating.

Most Mutations Are Lost: Why Learning Is Fundamental (Even For Australopithecines)

The flipside of the above calculations is that most mutations occurring from a single individual—even strongly beneficial ones—are lost.

Using the simple mathematical model, the probability that even a beneficial mutation will achieve fixation in the population, when starting from a single individual, is extremely low. J.B.S. Haldane calculated it at approximately 2 times the selective advantage—so even a 10% advantage is only 20% likely to reach fixation if it begins with a single individual! And for a 0.1% selective advantage, well, 0.2% doesn’t sound very encouraging, does it?

For those interested in the dirty mathematical details of simulating gene fixation, see (for instance) Kimura 1974 and Houchmandzadeh & Vallade 2011.

This low probability is because any gene carried by only one individual, or only a few individuals, is usually lost right away due to random chance while we’re on the initial part of the S-curve in the graph above. (As the number carrying the gene increases, the probability that everyone carrying it will die decreases.) So according to this naive model, we would expect individual australopithecines to have discovered meat-eating over and over again, hundreds if not thousands of times, before sheer luck finally allowed the behavior to spread throughout the population! Is that why it took millions of years to make progress?

Perhaps—but it seems doubtful. Meat-eating isn’t a single action: even if we assume that australopithecines were pure scavengers, it’s still a long, complicated sequence of behaviors involving finding suitable scraping/smashing rocks; looking for unattended carcasses; watching for their owners or other predators to return, which is probably a group behavior; grabbing any part that looked tasty; and using the rocks found earlier to help scrape off meat scraps, or to smash them open for marrow or brains. And hunting behavior is even more complex!

Of course, the naive mathematical model assumes that behavioral changes are purely under genetic control, and that individuals are not capable of learning. Since we know that the ability of humans to communicate knowledge by teaching and learning (known generally as “culture”) is greater than that of any other animal, it seems likely that the ability and inclination to learn from other australopiths was the primary mechanism by which our ancestors adapted a new mode of life that involved survival outside the forest—including meat-eating.

Note that chimpanzees can be taught all sorts of complicated skills, including how to make Oldowan stone tools—but they don’t seem to show any particular interest in teaching other chimps what they’ve learned.

Evidence That Increased Learning Ability Was The Key Hominin Adaptation During The Late Pliocene

We’ve just established that it’s very unlikely for a behavior discovered by one individual to spread throughout the population if it’s purely driven by a genetic mutation, even if it confers a substantial survival advantage—because the mathematics show that most individual mutations, even beneficial ones, are lost.

Here’s a summary of the physical evidence that our ancestors’ behavioral change was driven, at least in large part, by the ability to learn:

  • Body mass decreased by almost half between Ardipithecus ramidus (110#, 50kg) and Australopithecus africanus (65#, 30kg). Height also decreased slightly, from 4′ (122cm) to about 3’9″ (114cm). Clearly our ancestors’ adaptation to bipedal, ground-based living outside the forest didn’t depend on being big, strong, or physically imposing!
  • None of the physical changes appear to be a specific adaptation to anything but bipedalism, or to a larger brain case: faces became flatter and less prognathic, canines became shorter and less prominent, etc.
  • Despite a much smaller body, brain size increased from 300-350cc to 420-500cc. As brains are metabolically expensive (ranking behind only the heart and kidney by weight, and roughly equal to the GI tract—see Table 1 of Aiello 1997), this suggests that it was very important to conserve them.

Furthermore, it’s probably not a coincidence that bone marrow and brains are high in the same nutrients of which hominin brains are made—cholesterol and long-chain fats.

World Rev Nutr Diet 2001, 90:144-161.
Fatty acid composition and energy density of foods available to African hominids: evolutionary implications for human brain development.
Cordain L, Watkins BA, Mann NJ.

Scavenged ruminant brain tissue would have provided a moderate energy source and a rich source of DHA and AA. Fish would have provided a rich source of DHA and AA, but not energy, and the fossil evidence provides scant evidence for their consumption. Plant foods generally are of a low energetic density and contain virtually no DHA or AA. Because early hominids were likely not successful in hunting large ruminants, then scavenged skulls (containing brain) likely provided the greatest DHA and AA sources, and long bones (containing marrow) likely provided the concentrated energy source necessary for the evolution of a large, metabolically active brain in ancestral humans.

The learning-driven hypothesis fits with other facts we’ve already established. General-purpose intelligence is an inefficient way to solve problems:

…Intelligence is remarkably inefficient, because it devotes metabolic energy to the ability to solve all sorts of problems, of which the overwhelming majority will never arise. This is the specialist/generalist dichotomy. Specialists do best in times of no change or slow change, where they can be absolutely efficient at exploiting a specific ecological niche, and generalists do best in times of disruption and rapid change.” –Efficiency vs. Intelligence

Yet our hominin ancestors found success via greater intelligence rather than specific adaptations—most likely because of the cooling and rapidly oscillating climate previously discussed in Part I and Part IV. I’ll quote this paper again because it’s important:

PNAS August 17, 2004 vol. 101 no. 33 12125-12129
High-resolution vegetation and climate change associated with Pliocene Australopithecus afarensis
R. Bonnefille, R. Potts, F. Chalié, D. Jolly, and O. Peyron

Through high-resolution pollen data from Hadar, Ethiopia, we show that the hominin Australopithecus afarensis accommodated to substantial environmental variability between 3.4 and 2.9 million years ago. A large biome shift, up to 5°C cooling, and a 200- to 300-mm/yr rainfall increase occurred just before 3.3 million years ago, which is consistent with a global marine δ18O isotopic shift.

We hypothesize that A. afarensis was able to accommodate to periods of directional cooling, climate stability, and high variability.

The temperature graphs show that this situation continued. How did it affect our ancestors’ habitat and mode of life?

J Hum Evol. 2002 Apr;42(4):475-97.
Faunal change, environmental variability and late Pliocene hominin evolution.
Bobe R, Behrensmeyer AK, Chapman RE.

This study provides new evidence for shifts through time in the ecological dominance of suids, cercopithecids, and bovids, and for a trend from more forested to more open woodland habitats. Superimposed on these long-term trends are two episodes of faunal change, one involving a marked shift in the abundances of different taxa at about 2.8+/-0.1 Ma, and the second the transition at 2.5 Ma from a 200-ka interval of faunal stability to marked variability over intervals of about 100 ka. The first appearance of Homo, the earliest artefacts, and the extinction of non-robust Australopithecus in the Omo sequence coincide in time with the beginning of this period of high variability. We conclude that climate change caused significant shifts in vegetation in the Omo paleo-ecosystem and is a plausible explanation for the gradual ecological change from forest to open woodland between 3.4 and 2.0 Ma, the faunal shift at 2.8 +/-0.1 Ma, and the change in the tempo of faunal variability of 2.5 Ma.

In summary, 2.8 MYA is when things started to get exciting, climate-wise…and 2.6 MYA (the beginning of the Pleistocene) is when they started to get really exciting.

None of this is to say that the ability to learn was the only adaptation responsible for meat-eating: learning ability could easily have combined with other adaptations like inquisitiveness, aggressiveness, or a propensity to break things and see what happens.

Conclusion: A Tiny Difference Can Make All The Difference

  • Given the time-scale involved, a small selective advantage conferred by a small amount of meat-eating could easily have produced the selection pressure for meat-eating behavior to reach fixation in australopithecines.
  • Several lines of evidence—the mathematics of population genetics, the trends of australopithecine physical evolution, the ability of the nutrients in meat to build and nourish brains, and the increasingly colder, drier, and more variable climate—all point towards intelligence and the ability to learn (as opposed to physical power, or specific genetically-driven behavioral adaptations) being the primary source of the australopithecines’ ability to procure meat.

Don’t stop here! Continue to Part VII, “The Most Important Event In History”.

Live in freedom, live in beauty.

JS

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Big Brains Require An Explanation, Part I: Why Did Humans Become Smarter, Not Just More Numerous?

(This is a multi-part series. For the index, click here.)

How did we get from this:

Australopithecus afarensis reconstruction

Australopithecus afarensis (reconstruction)

To both this…

Hadzabe hunting Maribou storks on the shore of Lake Eyasi, Tanzania.

Hadzabe hunting Marabou storks

And this?

Shibuya Crossing 163

Shibuya Crossing, Tokyo

That’s more than a tripling of brain size—and an astounding increase in cultural complexity—in under 3 million years.

I’ve previously written about the currently accepted explanation, in this article: “Why Humans Crave Fat.” Here are a few bullet points:

  • Chimpanzees consume about one McDonalds hamburger worth of meat each day during the dry season—mostly from colobus monkeys, which they hunt with great excitement and relish.
  • Kleiber’s Law states that all animals of similar body mass have similar metabolic rates, and that this rate scales at only the 3/4 power of size. Therefore, in order for our brains to grow and use more energy, something else had to shrink and use less energy.
  • It takes a much larger gut, and much more energy, to digest plant matter than it does to digest meat and fat. This is why herbivores have large, complicated guts with extra chambers (e.g. the rumen and abomasum), and carnivores have smaller, shorter, less complicated guts.
  • The caloric and nutritional density of meat allowed our mostly-frugivorous guts to shrink so that our brains could expand—and our larger brains allowed us to become better at hunting, scavenging, and making tools to help us hunt and scavenge. This positive feedback loop allowed our brains to grow from perhaps 400cc (“Lucy”, Australopithecus afarensis) to over 1500cc (late Pleistocene hunters).
  • In support of this theory, the brains of modern humans, eating a grain-based agricultural diet, have shrunk by 10% or more as compared to late Pleistocene hunters and fishers.

(For a more detailed explanation, including links, references, and illustrations, read the original article.)

The Teleological Error

When discussing human evolution, it’s easy to fall into the error of teleology—the idea that evolution has a purpose, of which intelligence (specifically, self-conscious intelligence recognizable to our modern philosophical traditions, and producing something recognizable to us as ‘civilization’) is the inevitable expression and end result.

Geology and archaeology proves this is not so. For instance, 140 million years of saurian dominance (far more than the 65 million years mammals have so far enjoyed) apparently failed to produce any dinosaur civilizations: they simply became bigger, faster, and meaner until the K-T asteroid hit.

Thus endeth the reign of the dinosaurs.

Thus endeth the reign of the dinosaurs.

Likewise, the increased availability of rich, fatty, nutrient- and calorie-dense meat (enabled in large part by the usage of stone tools to deflesh bones, first practiced by our ancestors at least 2.6 million year ago, or MYA) does not, by itself, explain the over threefold increase in human brain size which began with the Pleistocene era, 2.6 MYA. When a climate shift brings more rain and higher, lusher grass to the African savanna, we don’t get smarter wildebeest, or even larger wildebeest. We get more wildebeest. Neither does this increase in the prey population seem to produce smarter hyenas and lions…it produces more hyenas and lions.

Contrary to their reputation, spotted hyenas are excellent hunters, and kill more of their own prey than lions do. (Many “lion kills” were actually killed by hyenas during the night—whereupon the lions steal the kill, gorge themselves, and daybreak finds the hyenas “scavenging” the carcass they killed themselves.) One 140-pound hyena is quite capable of taking down a wildebeest by itself.

So: if the ability to deflesh bones with stone tools allowed australopithecines to obtain more food, why didn’t that simply result in an increase in the Australopithecus population? Why would our ancestors have become smarter, instead of just more numerous?

The answer, of course, lies in natural selection.

Natural Selection Requires Selection Pressure

I don’t like the phrase “survival of the fittest”, because it implies some sort of independent judging. (“Congratulations, you’re the fittest of your generation! Please accept this medal from the Darwinian Enforcement Society.”)

“Natural selection” is a more useful and accurate term, because it makes no explicit judgment of how the selection occurs, or what characteristics are selected for. Some animals live, some animals die…and of those that live, some produce more offspring than others. This is a simple description of reality: it doesn’t require anyone to provide direction or purpose, nor to judge what constitutes “fitness”.

“Natural selection” still implies some sort of active agency performing the selection (I picture a giant Mother Nature squashing the slow and stupid with her thumb)—but it’s very difficult to completely avoid intentional language when discussing natural phenomena, because otherwise we’re forced into into clumsy circumlocutions and continual use of the passive voice.

(And yes, natural selection operates on plants, bacteria, and Archaea as well as on animals…it’s just clumsy to enumerate all the categories each time.)

Finally, I’m roughly equating brain size with intelligence throughout this article. This is a meaningless comparison across species, and not very meaningful for comparing individuals at a single point in time…but as behavioral complexity seems to correlate well with brain size for our ancestors throughout the Pleistocene, we can infer a meaningful relationship.

Therefore, we can see that “The availability of calorie- and nutrient-rich meat allowed our ancestors’ brains to increase in size” is not the entire story. The additional calories and nutrients could just as well have allowed us to become faster, stronger, or more numerous. For our ancestors’ brain size to increase, there must have been positive selection pressure for big brains, because big brains are metabolically expensive.

While at rest, our brains use roughly 20% of the energy required by our entire body!

In other words, the hominids with smaller brains were more likely to die, or to not leave descendants, than the hominids with larger brains.

What could have caused this selection pressure?

Ratcheting Up Selection Pressure: Climate Change and Prey Extinction

Just as “natural selection” is simply a description of reality, “selection pressure” is also a description of reality. It’s the combination of constraints that cause natural selection—by which some animals live, some die, and some reproduce more often and more successfully than others.

The selection pressure applied by one’s own species to reproductive choices—usually mate choice by females—is often called “sexual selection.” Sexual selection is, strictly speaking, part of natural selection, but it’s frequently discussed on its own because it’s so interesting and complex.

In this essay, I’m speaking primarily of the non-sexual selection parts of natural selection, for two reasons. First, because this article would expand to an unreadable size, and second, because understanding the influence of sexual selection in the Pleistocene would require an observational knowledge of behavior. Lacking time machines, anything we write is necessarily speculation.

In order for selection pressure to change, the environment of a species must change. I believe there are two strong candidate forces that would have selected for intelligence during the Pleistocene: climate change and prey extinction.

The Incredible Oscillating Polar Ice Caps: Understanding Pleistocene Climate

I’ve discussed Pleistocene climate change at length before. (Note: the Pleistocene epoch began approximately 2.6 MYa.)

“Unlike the long and consistently warm eons of the Jurassic and Cretaceous (and the Paleocene/Eocene), the Pleistocene was defined by massive climactic fluctuations, with repeated cyclic “ice ages” that pushed glaciers all the way into southern Illinois and caused sea level to rise and fall by over 100 meters, exposing and hiding several important bridges between major land masses.” –“How Glaciers Might Have Made Us Human”

Here is a chart of the estimated average surface temperature of the Earth, starting 500 MYA and ending today. Note the logarithmic time scale!

Click image for larger version.

To appreciate the magnitude and severity of Pleistocene climactic oscillation, note the tiny dip in temperature towards the right labeled “Little Ice Age”. This minor shift froze over the Baltic Sea and the Thames River, caused Swiss villages to be destroyed by glaciers, wiped out the Greenland Norse colonies, and caused famines in Europe which killed from 10% to 33% of the population, depending on the country.

Furthermore, the climate was changing very quickly by geological standards. Let’s zoom in on the Quaternary period (2.6 MYA – present), of which the Pleistocene forms the overwhelming majority (up to 11,800 years ago):

5 million years of temperature estimates from ice cores.  Cool!

Click image for larger version.

Note that massive 41,000 year climactic oscillations, each far greater than the Little Ice Age, began approximately 2.7 MYA—and the first known stone tools made by hominids (the Oldowan industry) are dated to 2.6 MYA.

Coincidence? Perhaps not.

Genetic Vs. Cultural Change

The behavior of most animals (and all plants) is primarily determined by genetic factors (“instinct”, “innate behavior”)—so in order to adapt to a changing environment, selection pressure must be exerted over many generations. For a short-lived species which reproduces a new generation ever year, or every few years, it might be possible to adapt to a 41,000 year climate cycle via natural selection.

However, for a long-lived species like humans, with generations measured in decades, genetic change is most likely too slow to fully adapt. We would have had to move in search of conditions that remained as we were adapted to…

…or we would have had to alter our behavior in cultural time, not genetic time.

Culture is the ability to transfer knowledge between generations, without waiting for natural selection to kill off those unable to adapt—and it requires both general-purpose intelligence and the ability to learn and teach. While space does not permit a full discussion of these issues, I recommend the PBS documentary “Ape Genius” for an entertaining look at the differences between modern human and modern chimpanzee intelligence and learning. (And I can’t resist noting that spotted hyenas outperform chimpanzees on intelligence tests that require cooperation: more information here and here, abstract of original paper here.)

You can watch the full video of “Ape Genius” here if you are a US resident. (If not, you’ll have to find a US-based proxy server.)

However, climate change is insufficient by itself to cause the required selection pressure. The overwhelming majority of known species survived these changes—including the glacial cycles of the past 740,000 years which scoured North America down to southern Illinois on eight separate occasions—because they could approximate their usual habitat by moving. Even plants can usually disperse their seeds over enough distance to keep ahead of glaciers.

Therefore, to fully explain the selection pressures that led to modern intelligence, we must look farther…to the consequences of intelligence itself.

Live in freedom, live in beauty.

JS

This series continues! Click here to read Part II.


Since my last update, The Gnoll Credo received yet another stellar review:

“A tale told with simple words that are beautifully put together…The most scathing yet beautiful insights into “civilized” humanity that I have ever seen…This novel made me reconsider my life and make serious, long-term changes that have brought nothing but positive results. That is the sign of a truly powerful book. Reading this novel, you will see the names of fictional characters and places, but you are not reading about them. You are reading about yourself.

My conclusion: must read.” –Steven Gray, “Book Review: The Gnoll Credo”

I don’t advertise or have a donation button: sales of TGC keep gnolls.org alive and updated with fresh, meaty content. In addition to the usual online retailers (Amazon.com, Barnes & Noble), US readers can buy signed copies directly from 100 Watt Press. (Outside the US? Click here for a list of international retailers.)

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Hunters Must Have Been Smart, They Invented Agriculture: A Review of Jack Brink’s “Imagining Head-Smashed-In” and George Frison’s “Survival By Hunting”

Imagining Head-Smashed-In, by Jack W. Brink

Imagining Head-Smashed-In,
by Jack W. Brink


One of the primary conceits of history is that nothing happened before agriculture. The Great Leap Forward! Between the Tigris and the Euphrates, the cradle of civilization! Page 1 of any sixth-grade world history textbook.

And before that?

Nothing, as far as we’re told. Unremitting savagery, a life nasty, brutish, and short, cavemen killing each other with clubs and dragging women by the hair. A life not worth a chapter, or even a page, to describe it.

Yet an awkward fact remains: these ‘savages’ were modern humans. In fact, they were taller, stronger, healthier, had larger brains and better teeth, and were longer-lived than the farmers that replaced them (see: Jared Diamond, Claire Cassidy).

And somehow these ‘savages’ managed to invent agriculture—a task much more difficult than practicing it. They discovered how and when to sow. They discovered how to plow, how to weed, how to protect crops against birds and rodents, how to harvest and thresh and grind and cook and bake…a suite of tasks that remained essentially unchanged for 10,000 years after their original discovery.

In other words, those ‘savages’ must have been pretty damned smart.

But how did they become so smart? It can’t have had anything to do with agriculture or anything we consider ‘civilized’, because they invented all that. What caused little 65-pound savanna apes with 350cc brains to evolve into Late Paleolithic modern humans with 1500cc brains?

Clearly there was much more to Paleolithic life than dumb savagery.

I will now turn this essay over to Jack W. Brink, archaeologist and author of “Imagining Head-Smashed-In: Aboriginal Buffalo Hunting on the Northern Plains.” From the Preface:

The book isn’t about what are traditionally considered the great historic achievements of our species. There are no magnificent cities built, no colossal monuments erected, no gigantic statues carved, no kingdoms conquered. It was very much this deviation from classical concepts of “civilization” that motivated me to write this book. Modern society seems to equate human achievement with monumental substance and architectural grandeur. Asked to name the greatest accomplishments of ancient cultures you would certainly hear of the Great Wall of China, Stonehenge, the Great Pyramids, and the civilizations that ruled Greece and Rome. Shunted off to the side are many ancient cultures that achieved greatness through their skill, knowledge, and ingenuity – cultures that managed to survive in demanding environments for extraordinary lengths of time without leaving towering monuments to themselves. In the coming pages I hope to show how simple lines of rocks stretching across the prairies are every bit as inspirational as rocks piled up in the shape of a pyramid.

This is a book about one of the truly remarkable accomplishments in human history. It is the story of an unheralded, unassuming, almost anonymous group of people who hunted for a living. They occupied an open, windswept, often featureless tract of land. They lived in conical skin tents that they lugged around with them in their search for food. A life of nearly constant motion negated permanent villages and cumbersome material possessions. They shared this immense landscape with herds of a wild and powerful beast – the largest animal on the continent. In a land virtually without limits, people of seemingly unsophisticated hunting societies managed to direct huge herds of buffalo to pinpoint destinations where ancient knowledge and spiritual guidance taught them massive kills could be achieved. It was an that guaranteed survival of the people for months to come, a that ensured their existence for millennia. Using their skill and their astonishing knowledge of bison biology and behaviour, bands of hunters drove great herds of buffalo over steep cliffs and into wooden corrals. In the blink of an eye they obtained more food in a single moment than any other people in human history. How they accomplished this is a story as breathtaking in scope and complexity as the country in which the events unfolded.

What follows is a fusion of archaeology and narrative, as Brink attempts to reconstruct the details of a buffalo jump—an event that last occurred in the 1800s, far outside anyone’s living memory. As he puts it:

Head-Smashed-In Buffalo Jump in southern Alberta, Canada, is but one of many places where herds of bison were brought to their deaths by the Native inhabitants of the Plains. It forms the nucleus around which my story unfolds. But this is not so much the story of one place, one people, or one time. It is the story of countless people who thrived over an enormous expanse of time and territory by orchestrating mass kills of bison. There were two reasons I wanted to write this book. First, to bring to a wider audience a story that I felt was so compelling and inspirational that it should not be allowed to fade from contemporary memory. And second, to do justice to the people who orchestrated these remarkable events.

The text of “Imagining Head-Smashed-In” runs to over 300 pages, which should be our first clue that this was not a trivial task. Indeed, reading it gives a nearly vertiginous sense of the skill, ingenuity, and sheer tenacity required to survive in the extreme environment of the Northern Great Plains. What we modern humans think of as “wilderness survival” basically consists of avoiding immediate death until someone in a helicopter rescues us—or, worst case, walking in one direction until we reach the safety and familiar problems of ‘civilization’, which is to say: other people. Obtaining food is not a concern, because humans can survive several weeks without food: ‘wilderness survival’ is a temporary state of privation, to be escaped as quickly as possible.

Yet for millions of years—the entire span of time and circumstances that shaped us from small, dumb apes into modern humans—daily life was far more challenging that what we think of today as ‘wilderness survival’. The problems of everyday life could not be postponed until we reached a hospital, a supermarket, or even a paved road—and they had to be addressed without maps, compasses, Gore-Tex, matches, or even a metal knife. Sickness, injury, and childbirth. Freezing cold, searing heat, pouring rain. And the continual, omnipresent drive of all life: hunger. The need to eat something nutritious so that you have the energy to live one more week, one more day, one more hour.

Yet Paleolithic humans met that challenge and mastered it—for we spread out of Africa and around the entire world, even to the smallest, most isolated Pacific islands. We survived in humid jungles and parched deserts, in howling blizzards and torrential downpours, on prairies and forests and valleys and mountains and beaches and anywhere there was living flesh for us to kill and eat. And we were such accomplished hunters and killers and eaters that we drove most of the big, slow animals to extinction.

Pyramids, in contrast, are uninteresting. All you need is tens of thousands of slaves to stack rocks until they die. Hunting is the real human history. Yet since it left behind nothing but stone points and bones smashed open for marrow, its stories are lost to us forever. All we can do is imagine.

And that is what Jack Brink does for us: he imagines one of the uncountable stories of the real human history.

Who could imagine that a book of North American archaeology could leave me near tears?

“Imagining Head-Smashed-In” is available directly from Athabasca University Press in hardback, paperback, and as a free Creative Commons-licensed PDF, or from Amazon.com.

Thanks to Tim Rangitsch (@acmebike, Acme Bicycles) for bringing this book to my attention.


Survival by Hunting, by George Frison

Survival by Hunting,
by George Frison


While “Imagining Head-Smashed-In” creates a strangely poignant narrative out of archeology, George Frison’s “Survival By Hunting” is a far more utilitarian book. If IHSA is a beautifully-constructed diorama in the museum located at the jump site, “Survival By Hunting” is one of the shovels used at the dig.

Just as IHSA is a combination of archaeology and narrative reconstruction, “Survival by Hunting” is a combination of archaeology and biography. Frison briefly tells his story as a child growing up in rural Wyoming on his grandfather’s ranch, and of both the culture and essential privation (he grew up during the Depression) that led to becoming a subsistence hunter at a young age. As a hunter he found many tools and traces of the Native American hunters who had previously inhabited the area, hunting the same game he had. An abiding interest in these remains led to a career in archaeology, which combines with his decades of experience hunting large animals to make him the leading authority on Prehistoric hunting techniques.

Though written very dryly, the book is an entertaining combination of factual academic recountings of artifact sites and his own personal experience. Instead of simply speculating how prehistoric hunters might have butchered mammoths with stone tools, Frison flies to Africa and tries it himself on an elephant carcass culled from a nature reserve—proving that stone tools are indeed sufficient to the task of cutting through elephant hide. And not content to guess at the force of a dart or spear thrown by an atlatl (spear-thrower) and whether it might be sufficient to kill a mammoth, he learns to make them himself—and tests them, again on an elephant carcass. Only someone with Frison’s experience at real-life game hunting, and Frison’s willingness to test his theories by experiment, could accumulate the knowledge he does—let alone assemble it into charmingly tentative hypotheses about the nature and significance of an archaeological site.

Reading “Survival by Hunting” is a bit like being on an dig oneself: startling artifacts of knowledge are strewn randomly about the narrative, often covered with dirt and mentioned only in passing. For instance:

Woodruff said that during the last half of the nineteenth century, [mountain] sheep were so plentiful that any time they were short of meat they hitched up a wagon, drove along the base of the steep east slope of the Absaroka Mountains, and loaded the wagon with sheep as they were shot and rolled to the bottom.

This offhand anecdote provides a glimpse of the cornucopia that must have been pre-contact North America, even after thousands of years of Native American hunting and subsequent extinctions. In contrast, our few remaining scraps of modern ‘wilderness’ are, for the most part, beautiful but lifeless high-altitude tundra. And hunting today is either completely prohibited or carefully managed, with thousands of would-be hunters vying for a tiny number of tags handed out by lottery—those tags costing many times in excess of the value of the meat.

As the book progresses, we learn that an elk antler tip can serve as an atlatl hook; that bison can squeeze through openings which cattle cannot; that pronghorn can run at over 45 MPH but refuse to jump or crash through a flimsy ‘fence’ made of brush; and hundreds of other small knowledge artifacts that only assemble themselves into a coherent whole in retrospect and upon reflection.

To summarize “Survival by Hunting”, I’ll quote the Preface:

Equally disturbing to me is the attitude students are acquiring towards hunting…students questioned about animal procurement strategies commonly respond, “When they got hungry, someone would kill a bison or whatever other animal was selected as the target for the day and bring it back to camp.” I believe such interpretations to be totally inadequate, and I hope that the contents of this book convince others of the vast reservoir of learned behavior involved in hunting.

All I have to say is: what George said.

(His criticism can be applied equally to many archaeologists, whose ignorance of basic physics, let alone hunting strategies, is blatantly obvious—but that’s another article for another time.)

“Survival by Hunting” may not have the grand narrative scope of “Imagining Head-Smashed-In”. But if you want to understand another tiny fragment of the real human history—which is how Plains hunters managed to kill mammoths, bison, and antelope on foot, using only sharp rocks and their wits—this book will get you there.

You can buy “Survival by Hunting” directly from the UC press, or at a discount from Amazon.com. (Sorry, no free PDF for this one.)

Live in freedom, live in beauty.

JS

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You might also enjoy “How Glaciers Might Have Made Us Human” and “When The Conclusions Don’t Match The Headlines: Darwin Is Still Right“.

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