Anurag Agrawal: Summer in the milkweed patch

AgrawalAnurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He lives in Ithaca, New York. His latest book, Monarchs and Milkweed, is available now.

It’s peak season for milkweed and the village of insects that make milkweed its home.  In my book on Monarchs and Milkweed, I devote an entire chapter to these diverse and fascinating other milkweed insects.  Below are photos from two days last week (July 6 and 7th), one set from my front yard and the other from Shawangunk National Grassland Preserve, both in NY State. All but two of the 11 specialized milkweed herbivores was seen on these four species of milkweed. Do you know which two species are missing?

The butterfly weed, Asclepias tuberosa.  Likes it dry.
Common milkweed, Asclepias syriaca, >90% of monarchs that make it to Mexico eat this as a caterpillar.
A. syriaca, mis-named because it was thought to be from Syria.
The purple milkweed, Asclepias purpurescens, rare in NY State, this spectacular individual was near the shawangunks.
Vegetative swamp milkweed, Asclepias incarnata.
Flowering swamp milkweed, Asclepias incarnata, complete with the swamp milkweed beetle, Labidomera clivicollis.
The poke milkweed, Asclepias exaltata, loves the partial shade. Note the nearly mature monarch.
The four-eyed milkweed longhorn beetle, Tetraopes tetrophthalmus. Note the four functional eyes!
Like all chewing insects on milkweed, Tetraopes deactivates the latex by clipping the veins.
Drippy toxic gooey stuff.
A little egg laid upon a leaf.  Monarch inside.
The first day or a monarch’s life, it makes a latex-free island before starting to feed on the leaf tissue inside the circle.
A week later, the monarch has grown 2000 times its original size.  This caterpillar has parasitic wasps eating it from the inside out.
The only fly known to eat milkweed, a leaf miner, feeds between layers of the leaf (larva is hidden here): Liriomyza asclepiadis.
Euchaetes egle, the milkweed tussock moth, a misnomer since it’s in the woolly bear family, Arctiidae.  Egg clutches hatch into hundreds of caterpillars… note the foamy fluff that the egg mass was delivered in.  These turn into large hairy orange and black caterpillars. Hmmmmm…. same colors as adult monarch butterflies.
A dead bee, like so many that get stuck in milkweed’s flowers. Why do they get stuck?
A tourist, not a real herbivore of milkweed.
Adult of the milkweed leaf beetle, Labidomera clivicollis, here on common milkweed.
Larva of the milkweed leaf beetle, Labidomera clivicollis.  Larvae of this species are apparently polymorphic, with grey or orange coloration. Closely related to the Colorado Potato Beetle.
An adult of the elusive milkweed stem weevil, Rhyssomatus lineaticollis, chewing on apical leaves of common milkweed.
Sometimes they poke the stem, as here on the poke milkweed, A. exaltata. No egg inside this one.
Other times eggs are laid in a row in the stem.
A trenched stem with milkweed stem weevil, Rhyssomatus lineaticollis, eggs.
Inside the stem, larval feeding and frass of the milkweed stem weevil, Rhyssomatus lineaticollis.
The milkweed stem weevil, Rhyssomatus lineaticollis, also deactivates the latex.  All the chewing herbivores of milkweed do it… more or less the same way, but with there own special twist.
No seed pods yet, but the small milkweed bug, Lygaeus kalmii, feeds on last year’s seeds and sucks milkweed’s sap (not the latex!) … The large milkweed bug has not yet arrived to NY State… it apparently cannot overwinter in the frozen north.
Aphis asclepiadis, one of three aphids that eats milkweed.  This species is greenish to brown to grey, typically lives on top of the plant, and is nearly always tended by ants.
And the Oleander aphid, Aphis nerii, usually bright yellow-orange.  Here with a winged adult, just founding a colony in Ithaca, NY.

Gary Saul Morson & Morton Schapiro: How the study of economics can benefit from the humanities

CentsEconomists often act as if their methods explain all human behavior. But in Cents and Sensibility, an eminent literary critic and a leading economist make the case that the humanities, especially the study of literature, offer economists ways to make their models more realistic, their predictions more accurate, and their policies more effective and just. Gary Saul Morson and Morton Schapiro argue that economists need a richer appreciation of behavior, ethics, culture, and narrative—all of which the great writers teach better than anyone. Original, provocative, and inspiring, Cents and Sensibility brings economics back to its place in the human conversation. Read on to learn more about how the study of economics is lacking, the misreading of Adam Smith, and how the humanities can help.

You clearly think that economics as traditionally practiced is lacking in fundamental ways. Why?
We believe that economic models could be more realistic, their predictions more accurate, and their policies more effective and just, if economics opened itself up to learning from other fields.

But don’t economists already work on subjects within the typical domain of such disciplines as psychology, sociology, anthropology, and history, among others?
It is true that economists apply their models very widely, but they often expropriate topics rather than sincerely engage with other fields. Too often economists act as if other disciplines have the questions, and economics has the answers. It is one thing to tread on the territory of another discipline; it is quite another to be willing to learn from it. Economists have often been imperialistic, presuming that the subject matter of other disciplines could be put on a “sound basis” if handled by economic models. They rarely ask whether the methods and assumptions of other disciplines might help economics. We need a dialogue, and a dialogue goes both ways.

You say that economics can be improved by interaction with the humanities, and especially the study of literature. In what ways does economics fall short so that an understanding of literature might help?
Economists have an especially hard time in three sorts of situations: when culture plays an important role, since one cannot mathematize culture; when contingency prevails and narrative explanation is required; and when ethical problems irreducible to economic models are important. For instance, whether to have a market in kidneys—one topic we address—is not a question that can be adequately addressed solely in economic terms. Economic thinking has something useful to say in many such cases, but not everything.  Great works of literature have offered the richest portraits of human beings we have. If social scientists understood as much about human beings as the great novelists, they could have produced pictures of human beings as believable as those of Jane Austen, George Eliot, or Leo Tolstoy, but none has even come close. The great novelists, who were often keen thinkers who discussed the complexities of human feeling and behavior, must have known something! They also produced the subtlest descriptions of ethical problems we have.

Isn’t economic imperialism the legacy of Adam Smith, the founder of the discipline?
Not at all. Economists, who seldom read The Wealth of Nations and rarely ask students to do so either, present a version of Adam Smith that is largely fictional. A thinker with an immensely complex sense of human nature, and who insisted that human beings care for others in ways that cannot be reduced to self-interest, is presented as a founder of rational choice theory, which presumes the opposite. What has happened is that a few Smithian ideas have been represented as the whole, and then a model based on them alone has been constructed and been attributed to him. While Adam Smith is often invoked to justify a simplistic view of human behavior guided by rational self-interest, and of economic policies that reject any interference with the free functioning of markets, his work was much more nuanced and sophisticated than that. To truly understand The Wealth of Nations, one must also read his complementary volume, The Theory of Moral Sentiments. Together, they provide the kind of far-reaching, inclusive economics celebrated in this book—an economics that takes other subjects seriously and embraces narrative explanations.

Don’t those two books contradict each other?
The idea that they do, and the question how the same author could have written them both, is often called “the Adam Smith problem.” In fact, the problem arises only when one misreads Smith. We offer a solution to the Adam Smith problem, which also shows how his thought looks forward to the great novelists to come.

You believe that narratives could teach economics a great deal. Is that why you argue that the humanities could be so useful in making economics more relevant?  How exactly does narrative help?
Stories are important, especially those told by the great realist novelists such as Tolstoy, Dostoevsky, Chekhov, and Austen. They help in at least two ways. First, in a world where genuine contingency exists, it is necessary to explain events narratively, and there are no better models for narratives about people in society than those in great novels. Second, novels foster empathy. Other disciplines may recommend empathy, but only novels provide constant practice in it. When you read a great novel, you identify with characters, inhabit their thought processes from within, and so learn experientially what it is to be someone else—a person of a different culture, class, gender, or personality. In a great novel you inhabit many points of view, and experience how each appears to the others. In this way, great novels are a source of wisdom. They appreciate people as being inherently cultural while embracing ethics in all its irreducible complexity.

That doesn’t sound like the way English courses are currently taught or accord with the currently predominant premises of literary theory.
Quite so. We are stressing a particular version of the humanities, what we think of as “the best of the humanities.” In a variety of ways, the humanities have been false to their core mission, which may be why so many students are fleeing them. In addition to the dominant trends of literary theory, we have witnessed a series of “spoof” disciplines, which purport to be humanistic but are actually something else. Sociobiological criticism, digital humanities, and other such trends proceed as if literature were too old fashioned to matter, and one has to somehow restore its importance by linking it—how doesn’t matter much—to whatever is fashionable. They all too often dehumanize the humanities, reducing their value not just to economics but to other fields as well. We celebrate, and recommend economists consider, the humanities at their best.

Are there any particular subjects within economics where engagement with the “best” of the humanities would be especially worthwhile?
There is a wide range of areas covered in the book—from economic development, to the economics of higher education, to the economics of the family—for which we believe a genuine dialogue between the humanities and economics is useful. We offer case studies in each of these areas, with some unanticipated results. We don’t pretend to conclude that dialogue in our book; we instead seek to get it started in a serious way.

Where do you see the dialogue of the two cultures leading?
The point of a real dialogue is that it is open-ended, that you don’t know where it will lead. It is surprising, and that is what makes it both stimulating and creative.

Gary Saul Morson is the Lawrence B. Dumas Professor of the Arts and Humanities and professor of Slavic languages and literatures at Northwestern University. His many books include Narrative and Freedom, “Anna Karenina” in Our Time, and The Words of Others: From Quotations to Culture. Morton Schapiro is the president of Northwestern University and a professor of economics. His many books include The Student Aid Game. Morson and Schapiro are also the editors of The Fabulous Future?: America and the World in 2040.

Happy birthday to Henry David Thoreau

by Jeffrey Cramer

Cramer“You would find him well worth knowing.” These are the words Nathaniel Hawthorne wrote to Henry Wadsworth Longfellow about “a man of thought and originality,” Henry David Thoreau.

July 12th marks the 200th anniversary of Thoreau’s birth in Concord, Massachusetts. Although at the time of his death in 1862 he was little more than a Ralph Waldo Emerson wannabe, today he is known around the world for his thoughtful writings on our place in the world. His writings on social reform inspired Tolstoy, Gandhi, Martin Luther King Jr., and protesters against the war in Vietnam. His natural history writings were a great impetus to John Muir, Rachel Carson, and Bill McKibben, and he is considered by many to be the father of the American environmental movement. His words in support of John Brown or against the Fugitive Slave Law are as courageous and as forthright as any written by our founding fathers. And as the man who “hears a different drummer” he has emboldened many readers to pursue their own unique paths with independence and confidence.

The world in which Thoreau lived was not so very different from ours. It was a time in which everything he believed and everything for which his country stood was being challenged. We live in hard times of a different character, when our country, when the world, is being divided politically, morally, and ethically. It is a time of deep personal reflection, deliberate and attentive questioning, and perhaps the most necessary thing of all, open dialogue and conversation. “We are all schoolmasters,” Thoreau wrote, showing us that we all have something to share. But he also said that we should “seek to be fellow students,” reminding us that we all have something to learn.

Thoreau can teach and inspire and antagonize and outrage, but ultimately give us something against which to try our own lives and that is what great writing offers the reader. In reading Thoreau we may not always find the answer to our questions, but we find the question. We may find words we agree with or we may find words we cannot agree with, in part or at all, but we do find a challenge to our complacency.

When George Eliot reviewed Walden, she said she would “Let Mr. Thoreau speak for himself.” Following Eliot’s advice, here are a few phrases in which Thoreau speaks for himself.


Nothing is so much to be feared but fear.

It costs us nothing to be just.

How insufficient is all wisdom without love.

What does education often do! It makes a straight-cut ditch of a free meandering brook.

I have sometimes heard a conversation beginning again when it should have ceased for lack of fuel.

A government which deliberately enacts injustice, and persists in it, will at length ever become the laughingstock of the world.

Any truth is better than make-believe.



Tuesday’s Trot – Polish Koniks

From page 374 in Horses of the World:

5 things to know about the Polish Konik:

1. Its Polish name Konik polski means “small Polish horse.” Outside of Poland it is sometimes called a “Tarpan,” even though the breed is domesticated, whereas the Tarpan is a wild animal.

2. Polish Koniks are the direct issue of the Tarpan, whose look and unique coat they have inherited. Along with the Portuguese Sorraia, this horse has remained closest to its wild ancestor.

3. Koniks were once hunted as game. A large number of Koniks are still bred in conditions close to a wild environment.

4. The Konik is active, very intelligent, gentle and docile, but sometimes independent and assertive. It is very strong for its size, has good endurance, and is very rustic, hardy, resilient, and well adapted to a harsh climate. It is also very fertile and lives a long time.

5. Once used for farm work, it is also suited for riding and driving. Its gentleness makes it well suited to equitherapy.

Horses of the World
Élise Rousseau
Illustrated by Yann Le Bris
Translated by Teresa Lavender Fagan
Sample Entry

Horses of the World is a comprehensive, large-format overview of 570 breeds of domestic and extant wild horses, including hybrids between the two and between domestic breeds and other equids, such as zebras. This beautifully illustrated and detailed guide covers the origins of modern horses, anatomy and physiology, variation in breeds, and modern equestrian practices. The treatment of breeds is organized by country within broader geographical regions—from Eurasia through Australasia and to the Americas. Each account provides measurements (weight and height), distribution, origins and history, character and attributes, uses, and current status. Every breed is accompanied by superb color drawings—600 in total—and color photographs can be found throughout the book.

Describing and depicting every horse breed in existence, Horses of the World will be treasured by all who are interested in these gorgeous animals.

Big Pacific – Passionate Pacific

Watch the fourth episode of Big Pacific, “Passionate Pacific,” on your local PBS station at 8pm Eastern, Wednesday, July 12th. The companion book is available now from Princeton University Press.

The largest ocean on planet Earth, the vast and unfathomable Pacific is inhabited by an extraordinary wealth and diversity of animal life. This multitude of species is united by a common drive—the need to reproduce—but that drive is expressed in ways as different as the creatures themselves.

Clownfish and Anemone

A clownfish lurks amid the fronds of a poisonous Anemone.

The home life of the clownfish is unusual—these small, brightly colored fish live out their lives amid the fronds of sea anemones, exuding a mucus-like covering that protects them from the anemone’s poisonous sting. Up to a dozen clownfish may live in the embrace of a single anemone, protected from predators by their host’s venom. In return, the clownfish consume parasites that could harm the anemone, and their movements as they swim help waft food towards the stationary anemone. All clownfish are born male, but within each of these miniature colonies, one of these males will become dominant and develop into a female. In turn, this female will select one and only one of the remaining males as a mate, leaving the rest to live out their lives in cloistered celibacy. The chosen male has the tasks of fertilizing the hundreds of eggs released by the female when she spawns and of guarding them without respite until they hatch ten days later.

Grunion run

Grunion carpet the shore during their mating run.

The reproductive life of the Gulf grunion is more hazardous and dramatic, played out in the liminal zone where the ocean meets the shore in the Gulf of California. Riding the high tide produced by the full moon, a wave of female grunion pitches onto the beach, digging into the sand to find a place to lay their eggs. That wave is followed in quick succession by the males, who wrap themselves around their half-buried mates to fertilize the eggs. Though the process takes only minutes, the fish quickly returning to the water to avoid suffocation, it leaves the grunion vulnerable. The beach, densely carpeted with silvery bodies, is an open buffet for predatory birds such as gulls, but the sheer mass of grunion ensures that plenty survive. The grunion hatchlings remain buried in the sand until the next full moon tide allows them to make their way back into the ocean.

Seahorses with tails entwined

Pot-bellied seahorses entwine their tails for a mating dance.

The Pot-bellied seahorse prefers a more relaxed courtship. Having identified a potential mate, the male seahorse brightens his stomach pouch to a vivid yellow. The female responds with her own display of color, and the two entwine their tails for an underwater dance that can last for up to twenty minutes as the seahorses pirouette and twirl around the warm, shallow waters in which they live. At the consummation of the dance, the two belly-to-belly, the female squirts her eggs into an opening in the male’s pouch and the two separate. Once the eggs hatch, the male carries his hundreds of offspring in his pouch for up to a month, before releasing them to float away.

Bird Fact Friday – The spectacular Resplendent Quetzal

From page 270 in The New Neotropical Companion:

Male Resplendent Quetzal, in all its splendor. Photo by Gina Nichol.

Arguably the most spectacular member of the trogon family is the Central American Resplendent Quetzal, which is said to be the inspiration for the legendary phoenix. Guatemala’s monetary unit is the quetzal, and the bird’s image appears on all currency. Quetzals inhabit the cloud forests of Middle America, migrating to lower elevations seasonally. Most striking about the quetzal’s plumage is the brilliant green male’s elongated upper tail coverts, graceful plumes that stream down well below the actual tail, making the bird’s total length fully 61 cm (24 in). Females are a duller green and lack the elaborate tail plumes.

The New Neotropical Companion
John Kricher
Chapter One

The New Neotropical Companion is the completely revised and expanded edition of a book that has helped thousands of people to understand the complex ecology and natural history of the most species-rich area on Earth, the American tropics. Featuring stunning color photos throughout, it is a sweeping and cutting-edge account of tropical ecology that includes not only tropical rain forests but also other ecosystems such as cloud forests, rivers, savannas, and mountains. This is the only guide to the American tropics that is all-inclusive, encompassing the entire region’s ecology and the amazing relationships among species rather than focusing just on species identification.

The New Neotropical Companion is a book unlike any other. Here, you will learn how to recognize distinctive ecological patterns of rain forests and other habitats and to interpret how these remarkable ecosystems function—everything is explained in clear and engaging prose free of jargon. You will also be introduced to the region’s astonishing plant and animal life.

Craig Bauer on unsolved ciphers

In 1953, a man was found dead from cyanide poisoning near the Philadelphia airport with a picture of a Nazi aircraft in his wallet. Taped to his abdomen was an enciphered message. In 1912, a book dealer named Wilfrid Voynich came into possession of an illuminated cipher manuscript once belonging to Emperor Rudolf II, who was obsessed with alchemy and the occult. Wartime codebreakers tried—and failed—to unlock the book’s secrets, and it remains an enigma to this day. In Unsolved, Craig Bauer examines these and other vexing ciphers yet to be cracked. Recently he took the time to answer some questions about his new book.

Why focus on unsolved ciphers?

They’re much more intriguing because they could be concealing anything. Some might reveal the identities of serial killers. Others could unmask spies, rewrite history, expose secret societies, or even give the location of buried treasure worth millions. This sense of mystery is very appealing to me.

Did you try to solve the ciphers yourself first?

There are so many unsolved ciphers that I realized I would never finish writing about them if I kept stopping to try to solve them. There’s one that I’m confident I could solve, but instead of doing so, I simply presented the approach I think will work and am leaving it for a reader to pursue. I expect that several of them will be solved by readers and I look forward to seeing their results!

Does someone who wants to attack these mysteries need to know a lot of mathematics or have computer programming skills?

No. Many of the ciphers were created by people with very little knowledge in either area. Also, past solvers of important ciphers have included amateurs. One of the Zodiac killer’s ciphers was solved by a high school history teacher. Some of the ciphers might be solved in a manner that completely bypasses mathematics. A reader may find a solution through papers the cipher’s creator left behind, perhaps in some library’s archives, in government storage, or in a relative’s possession. I think some may be solved by pursuing a paper trail or some other non-mathematical avenue. Of course, there are mathematical challenges as well, for those who have the skills to take them on. The puzzles span thousands of years, from ancient Egypt to today’s online community. Twentieth century challenges come from people as diverse as Richard Feynman (a world-class physicist) and Ricky McCormick (thought to have been illiterate).

Are all of the unsolved ciphers covered in the book?

No, far from it. There are enough unsolved ciphers to fill many volumes. I limited myself to only the most interesting examples, and still there were too many! I originally set out to write a book about half the size of what was ultimately published. The problem was that there was so much fascinating material that I had to go to 600 pages or experience the agony of omitting something fabulous. Also, unsolved ciphers from various eras are constantly coming to light, and new ones are created every year. I will likely return to the topic with a sequel covering the best of these.

Which cipher is your favorite?

I’m the most excited about the Paul Rubin case. It involves a cipher found taped to the abdomen of a teenage whiz-kid who was found dead in a ditch by the Philadelphia airport, way back in 1953. While I like well-known unsolved ciphers like the Voynich Manuscript and Kryptos, I have higher hopes for this one being solved because it hasn’t attracted any attention since the 1950s. The codebreakers have made a lot of progress since then, so it’s time to take another look and see what can be learned about this young man’s death. I felt it was very important to include cases that will be new even to those who have read a great deal about cryptology already and this is one such case.

Should the potential reader have some prior knowledge of the subject?

If he or she does, there will still be much that is new, but for those with no previous exposure to cryptology, everything is explained from the ground up. As a teenager I loved books at the popular level on a wide range of topics. In particular, the nonfiction of Isaac Asimov instilled in me a love for many subjects. He always started at the beginning, assuming his readers were smart, but new to the topic he was covering. This is the approach that I have taken. I hope that the book finds a wide readership among the young and inspires them in the same way Asimov inspired me.

Is there anything that especially qualifies you to write on this topic?

Early work on this book was supported by the National Security Agency through their Scholar-in-Residence program at the Center for Cryptologic History. They wanted me in this role because, while I have a PhD in mathematics and have carried out mathematical research in cryptology, I also have a passion for history and other disciplines. In fact, both of my books have the word “history” in their titles. The journal Cryptologia, for which I serve as the editor-in-chief, is devoted to all aspects of cryptology, mathematical, historical, pedagogical, etc. My love of diverse fields allows me to write with enthusiasm about ciphers in music, art, criminal cases, ancient history, and other areas. The broad approach to the subject is more entertaining and ensures that there’s something in the book for nearly every reader.

BauerCraig Bauer is professor of mathematics at York College of Pennsylvania. He is editor in chief of the journal Cryptologia, has served as a scholar in residence at the NSA’s Center for Cryptologic History, and is the author of Unsolved! The History and Mystery of the World’s Greatest Ciphers from Ancient Egypt to Online Secret Societies. He lives in York, Pennsylvania.

Princeton University Press awarded the Lyman H. Butterfield Award

At the 2017 annual meeting of the Association for Documentary Editing held in Buffalo, New York, Princeton University Press was awarded the Lyman H. Butterfield Award, given annually by the Association since 1985 “to an individual, project, or institution for recent contributions in the areas of documentary publication, teaching, and service.” The award is granted in memoriam of Lyman Butterfield, whose editing career included contributions to The Papers of Thomas Jefferson, the editing of the Adams Family Papers, and publishing The Letters of Benjamin Rush. Princeton University Press is a leader in the field that has embraced the world of digital scholarship while continuing to support book editions.

The award was presented by last year’s winner, Roger Bruns, and accepted on behalf of the Press by Barbara Oberg, General Editor Emerita of The Jefferson Papers. Bruns’ comments follow:

One scholar wrote of the Jefferson edition, “…, the ever-increasing attention over the years to thorough translation of multiple languages and powerful, thoughtfully chosen illustrations make for a stimulating and more comprehensive reading experience. Precision is the hallmark of the Princeton University Press. Quality, durability, and consistency frame the content––matching the degree of adoration that the historical Jefferson himself brought to his books and papers.” The Press has published sixty volumes of the Jefferson Papers in three series and throughout this time its commitment to the best standards has never wavered.

The contributions of Princeton University Press to historical documentary editing go far beyond the Jefferson Papers. The Press published all sixty-nine volumes of The Papers of Woodrow Wilson, edited by Arthur Link. It also published both volumes of the Letters of Benjamin Rush in 1951 and both volumes of the Political Correspondence and Public Papers of Aaron Burr in 1983.

But historical projects are certainly not the only beneficiaries of this commitment to scholarly publishing. Just listen to the some of the multitude of subjects, the unprecedented list of individual whose papers the Press has, with precision and efficiency, published in the last few decades. It has published collected works of Carl Jung, Kierkegaard’s Writings, a critical edition of W. H. Auden, Collected Writings of Samuel Taylor Coleridge, and The Writings of Henry David Thoreau.

It has published the Collected Works of Paul Valery; the Collected Works of Goethe; editions of Erich Neumann and St. John Perse, The Collected Dialogues of Plato, and the Complete Works of Aristotle. I’m surprised that the Press has not published the secret diaries of King Tut.

This record represents a remarkable dedication to a broad and deep presentation of important contributions to literature, classicism, history, poetry, science, and music. When you stop and think about the breadth and amount of scholarship it seems, it is, astonishing.

In addition to this remarkable publishing legacy, the Press also entered into a unique collaboration with Hebrew University of Jerusalem in co-sponsoring a scholarly edition of The Collected Papers of Albert Einstein. The project has published fourteen volumes to date, with each volume appearing first with the documents in their original language and then reissued in English translation.


Peter Dougherty, the director of Princeton University Press adds, “For my colleagues at PUP and for the editors of our documentary book projects, we are honored to receive the 2017 Lyman H. Butterfield Award and thrilled that our long-time publishing partner and dear friend Barbara Oberg [has accepted] it for us.

The award is timely because it recognizes Peter’s distinguished leadership of the Press for more than a decade. He is stepping down as director later this year.

Peter Ungar: It’s not that your teeth are too big: your jaw is too small

We hold in our mouths the legacy of our evolution. We rarely consider just how amazing our teeth are. They break food without themselves being broken, up to millions of times over the course of a lifetime; and they do it built from the very same raw materials as the foods they are breaking. Nature is truly an inspired engineer.

But our teeth are, at the same time, really messed up. Think about it. Do you have impacted wisdom teeth? Are your lower front teeth crooked or out of line? Do your uppers jut out over your lowers? Nearly all of us have to say ‘yes’ to at least one of these questions, unless we’ve had dental work. It’s as if our teeth are too big to fit properly in our jaws, and there isn’t enough room in the back or front for them all. It just doesn’t make sense that such an otherwise well-designed system would be so ill-fitting.

Other animals tend to have perfectly aligned teeth. Our distant hominin ancestors did too; and so do the few remaining peoples today who live a traditional hunting and gathering lifestyle. I am a dental anthropologist at the University of Arkansas, and I work with the Hadza foragers of Africa’s great rift valley in Tanzania. The first thing you notice when you look into a Hadza mouth is that they’ve got a lot of teeth. Most have 20 back teeth, whereas the rest of us tend to have 16 erupted and working. Hadza also typically have a tip-to-tip bite between the upper and lower front teeth; and the edges of their lowers align to form a perfect, flawless arch. In other words, the sizes of Hadza teeth and jaws match perfectly. The same goes for our fossil forebears and for our nearest living relatives, the monkeys and apes.

So why don’t our teeth fit properly in the jaw? The short answer is not that our teeth are too large, but that our jaws are too small to fit them in. Let me explain. Human teeth are covered with a hard cap of enamel that forms from the inside out. The cells that make the cap move outward toward the eventual surface as the tooth forms, leaving a trail of enamel behind. If you’ve ever wondered why your teeth can’t grow or repair themselves when they break or develop cavities, it’s because the cells that make enamel die and are shed when a tooth erupts. So the sizes and shapes of our teeth are genetically pre-programmed. They cannot change in response to conditions in the mouth.

But the jaw is a different story. Its size depends both on genetics and environment; and it grows longer with heavy use, particularly during childhood, because of the way bone responds to stress. The evolutionary biologist Daniel Lieberman at Harvard University conducted an elegant study in 2004 on hyraxes fed soft, cooked foods and tough, raw foods. Higher chewing strains resulted in more growth in the bone that anchors the teeth. He showed that the ultimate length of a jaw depends on the stress put on it during chewing.

Selection for jaw length is based on the growth expected, given a hard or tough diet. In this way, diet determines how well jaw length matches tooth size. It is a fine balancing act, and our species has had 200,000 years to get it right. The problem for us is that, for most of that time, our ancestors didn’t feed their children the kind of mush we feed ours today. Our teeth don’t fit because they evolved instead to match the longer jaw that would develop in a more challenging strain environment. Ours are too short because we don’t give them the workout nature expects us to.

There’s plenty of evidence for this. The dental anthropologist Robert Corruccini at Southern Illinois University has seen the effects by comparing urban dwellers and rural peoples in and around the city of Chandigarh in north India – soft breads and mashed lentils on the one hand, coarse millet and tough vegetables on the other. He has also seen it from one generation to the next in the Pima peoples of Arizona, following the opening of a commercial food-processing facility on the reservation. Diet makes a huge difference. I remember asking my wife not to cut our daughters’ meat into such small pieces when they were young. ‘Let them chew,’ I begged. She replied that she’d rather pay for braces than have them choke. I lost that argument.

Crowded, crooked, misaligned and impacted teeth are huge problems that have clear aesthetic consequences, but can also affect chewing and lead to decay. Half us could benefit from orthodontic treatment. Those treatments often involve pulling out or carving down teeth to match tooth row with jaw length. But does this approach really make sense from an evolutionary perspective? Some clinicians think not. And one of my colleagues at Arkansas, the bioarchaeologist Jerry Rose, has joined forces with the local orthodontist Richard Roblee with this very question in mind. Their recommendation? That clinicians should focus more on growing jaws, especially for children. For adults, surgical options for stimulating bone growth are gaining momentum, too, and can lead to shorter treatment times.

As a final thought, tooth crowding isn’t the only problem that comes from a shorter jaw. Sleep apnea is another. A smaller mouth means less space for the tongue, so it can fall back more easily into the throat during sleep, potentially blocking the airway. It should come as no surprise that appliances and even surgery to pull the jaw forward are gaining traction in treating obstructive sleep apnea.

For better and for worse, we hold in our mouths the legacy of our evolution. We might be stuck with an oral environment that our ancestors never had to contend with, but recognising this can help us deal with it in better ways. Think about that the next time you smile and look in a mirror.

Evolution’s Bite: A Story of Teeth, Diet, and Human Origins by Peter Ungar is out now through Princeton University Press.Aeon counter – do not remove

UngarPeter S. Ungar is Distinguished Professor and director of the Environmental Dynamics Program at the University of Arkansas. He is the author of Evolution’s Bite: A Story of Teeth, Diet, and Human Origins, Teeth: A Very Short Introduction and Mammal Teeth: Origin, Evolution, and Diversity and the editor of Evolution of the Human Diet: The Known, the Unknown, and the Unknowable. He lives in Fayetteville, Arkansas.

This article was originally published at Aeon and has been republished under Creative Commons.

Big Pacific – Voracious Pacific

Watch the third episode of Big Pacific, “Voracious Pacific,” on your local PBS station at 8pm Eastern, Wednesday, July 5th. The companion book is available now from Princeton University Press.

The inhabitants of the Pacific Ocean are united by the need to feed, the constant quest for sustenance. Many of these inhabitants feed on each other—only a handful of the largest and most dangerous are free of the threat of becoming somebody else’s lunch. Any evolutionary adaptation that makes it easier to acquire food confers an advantage in the battle for survival, and the Pacific showcases many remarkable adaptations and specializations.

Double-crested cormorant

A double-crested cormorant dries its wings after a dive.

The double-crested cormorant dives for fish, plummeting out of the air to plunge into shallow coastal waters. The light, hollow bones that make it easy for other birds to soar would make it difficult for the cormorant to remain submerged; instead it has evolved with heavier bones, lower body fat, and feathers that absorb water, allowing it to swim underwater for up to thirty seconds at a time, propelled by its wings and webbed feet. After a dive, the now waterlogged bird will need to dry its feathers before it can fly again, and they can be easily spotted on rocky shores, standing with wings outstretched to dry in the sun. These cormorants are so well adapted to hunting underwater that their young will sometimes take to the water even before learning to fly.

Peppered moray eel

A peppered moray eel slithers across the rocks in search of crabs

If the Pacific is home to birds that hunt underwater, it is only fitting that there should also be fish that hunt on land. Moray eels have long been known as effective predators, possessed of powerful jaws from which few victims escape. Morays typically lurk in crevices or holes in underwater reefs, waiting for an unsuspecting meal to swim by, but the peppered moray takes a more proactive approach. These eels will slither out of the water at low tide, dipping in and out of rock pools to avoid suffocation, searching for crabs. The peppered moray is the only member of the moray family known to leave the water in this way.

Nomura's jellyfish

Nomura’s jellyfish is one of the largest jellyfish, but feeds though hundreds of tiny mouths.

Paradoxically, some of the largest denizens of the ocean feed on the smallest prey. The blue whale is the largest animal on the planet – a full-grown blue whale can reach a hundred feet in length and two hundred tonnes in weight—but it feeds on krill, small crustaceans barely an inch in length, filtering vast draughts of water through baleen plates in its mouth to trap the tiny krill. Manta rays feed on smaller fry still, sweeping up plankton as they glide through the water on wing-like fins that can span 23 feet in width. But perhaps the most extraordinary is the Nomura’s jellyfish. These giant jellyfish start life as a polyp the size of a pinhead with a mouth barely a millimeter wide but in the space of a year they grow to some six feet in diameter and more than 400 pounds in weight. Their mouths do not grow with them; instead the jellyfish develops hundreds of tiny mouths, allowing them to filter an Olympic swimming pool of water for plankton every day. Voracious indeed!

See dazzling footage of these animals and many more in the next episode of Big Pacific.