John Kricher on The New Neotropical Companion (revised & expanded)

The New Neotropical Companion by John Kricher 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.

What originally focused your interest in the Neotropics and why did you want to write about the region? 

JK: When I was early in my career in ecology and ornithology, way back in the 1970s, I longed to experience the tropics, to be in hot, steamy equatorial jungles, the ecosystems of the world that harbor the most species.  There was so much I wanted to see, especially bird species. It was really birds that got me there.  I wanted to see firsthand the various tropical birds, the antbirds, parrots, cotingas, trogons, toucans, etc.  To me, these were pure glamor birds, and so many of them.  Reading about them only intensified my need to go and see them firsthand.  So, I jumped on the first opportunity that came along to get myself passage into “the Torrid Zone.”

And what was that opportunity? 

JK: I met a man who was to become a long-time close friend, Fred Dodd.  Fred had just started a company called International Zoological Expeditions (IZE) and he was organizing trips to Belize for college classes.  I saw such a trip as my ideal way to get a foothold in the tropics.  And it worked!  My first tropical experience was to take a class of about 30 students from Wheaton College to Belize and Guatemala over semester break in January of 1979.  The unexpected and challenging experiences we had as we faced numerous logistical hurdles in this admittedly pioneering effort would, in themselves, make a pretty cool book.  But we did it, I loved it, and wanted more, much more.  When I meet my first Tropical Ecology students at alumnae gatherings they all want to relive memories of “the Belize trip.”  We tell the same stories over and over and never seem to tire of it.  Going to Belize, getting to the American tropics, was a watershed experience for me, transforming my career.

Why did you feel the need to write A Neotropical Companion and how did you choose that title? 

JK: It was hard to systematically organize information to present to students about the American tropics.  In the late 1970s information about the tropics was widely scattered and incomplete.  For example, there was no single book I could recommend to my students to prepare them for what would await them in the field.  At the same time, I read multiple journal articles on everything from tree diversity to army ant behavior and it was such cool stuff.  I loved telling the students my various “stories” gleaned from the ecological literature.  As I made more and more visits to Central and South American countries my own perspective was greatly enhanced so I could bring something to the table, so to speak, directly from personal experience.  My knowledge base grew in leaps and bounds and I kept expecting that any day a book would be published that would bring together what I was experiencing and enjoying.  It never was.  So, I thought I could adapt my course information into an introductory book. That was what spawned A Neotropical Companion.  The illustrations in the first edition, published in 1989, were by one of my tropical ecology students who adapted them from her field notebook kept when she took my tropical course in Belize.  As for the title, when Judith May, editor at Princeton University Press, read my manuscript she liked it and said, with enthusiasm, that she had “the perfect title” for the book.  It was Judith who gave it its name.

Your first edition was nicknamed “The Little Green Book.”  Did its popularity surprise you? 

JK: It did.  It was flattering that many folks told me they carried my little green book on various tropical trips and found it very informative and easy to read.  And it was indeed a little green book that conveniently fit in a pocket or backpack.  I knew I had barely scratched the surface with regard both to breadth and depth of information but I was very pleased and a bit surprised by the warm reception the book received.  And as I began making frequent trips to lowland Amazonia as well as Andean ecosystems I knew it was time to expand and revise the book.  The little green book needed to grow.  It did that with the publication of the second edition in 1997 and obtained what I consider its “full maturity,” a coming of age, in the present edition.  It is no longer green and no longer little but much more comprehensive and far better illustrated than its predecessors. This is the book I had always wanted to write.

What is the biggest thing that has changed with regard to visiting the American tropics since you first wrote your Little Green Book? 

JK: In the nearly 30 years since I published the first edition the American tropics has become much easier and more comfortable to visit.  Good tourist lodges were relatively few when I first visited the tropics and now they abound. Talented local guides skilled in finding wildlife take groups to see all manner of fantastic species such as Harpy Eagle, for example. There are now tours in which you are virtually assured of getting fine views of fully wild jaguars.  I wrote in the first edition about being very careful as to what you eat, where you go, and various health concerns.  I scaled that way back in my new edition because it is no longer necessary to include it.  A determined traveler may make trips virtually anywhere in the Neotropics and do so safely and in relative comfort, though some areas do remain rugged and challenging.  There are now even tours to Theodore Roosevelt’s famous “River of Doubt,” once considered a huge challenge to explorers.  This was unheard of when I began my travel to the tropics.

Are you still always being asked about encountering snakes and biting insects in the tropics?

JK: Indeed, I am.  And to be truthful, snakes, including many venomous species, are relatively common if not abundant in some tropical venues, though they are not necessarily easy to find unless one is skilled at searching for them.  It is important to be vigilant when on trails and walking around lodges and field stations, especially at night or after a rainfall.  Snakes may be out and about.  But very few encounters result in venomous snake bites.  I encourage people to experience snakes as interesting and beautiful animals and, as one would a lion on the Serengeti, make sure to maintain a respectful distance.  In Trinidad, my group encountered a huge bushmaster, the largest of the Neotropical venomous snakes.  It was crossing a road late at night and was caught in the headlights of our van.  We all saw it well and from a safe distance, a thrilling sight.  As for insects, I have rarely been very bothered by them, especially mosquitos, but if you travel in rainy season mosquitos may be locally abundant and highly annoying.  Visitors to the tropics must really beware of bees and wasps and even ants, some of which act aggressively if disturbed and may pack a powerful sting.  One ant is called the “bullet ant” because it bites you, holds on, and then stings you. The sting allegedly feels like you were hit with a bullet.

Now that The New Neotropical Companion is complete do you have any plans for further exploration of the Neotropics or are you satisfied that you have done all you set out to do?

JK: I continue to be strongly drawn to the American tropics.  I have very recently visited Honduras and Cuba.  I have plans for trips to numerous other Neotropical venues, from Guyana to Peru and Amazonia.  The wonder of the regional biodiversity has always compelled me to want to see more, go to new areas as well as revisit places I have come to know well, and just keep on learning.  No two visits to the tropics, even to a place where one has been repeatedly, are the same.  The more you go, the more you see.  So, I keep going.

John Kricher is professor of biology at Wheaton College. His many books include Tropical Ecology, The Balance of Nature: Ecology’s Enduring Myth, and Galápagos: A Natural History.

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

UngarWe 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

Peter S. Ungar is Distinguished Professor and director of the Environmental Dynamics Program at the University of Arkansas. He is the author of 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.

Browse Our New Biology 2017-2018 Catalog

In our Biology 2017-2018 catalog you will find a host of new books, from an in depth look at the complex relationship between one of our most beautiful butterflies and a family of poisonous plants to a fascinating exploration of the role of beauty and attraction in sexual selection.

If you will be at ESA in Portland, we will be in booth 703. Join us for a reception with wine and light refreshments to celebrate our new titles and meet our authors at 5pm, Tuesday, August 8th. Or stop by any time to check out our full range of titles in biology and related fields.

In Monarchs and Milkweed, Anurag Agrawal draws on more than a decade of research to bring an unsurpassed account of the coevolution of the monarch butterfly and the milkweed. Monarchs lay their eggs exclusively on milkweed plants, on which they feed in the early stages of their lives as caterpillars. The milkweed has evolved a battery of defensive characteristics to reduce the depredations of monarch caterpillars; in turn, monarchs have evolved their own means of overcoming these defenses. Learn about this evolutionary arms race, and much more besides in Monarchs and Milkweed.

Monarch

In his theory of sexual selection, Darwin argued that animals have “a taste for the beautiful” that governs their attraction to potential mates. But in what does this taste reside? How does it affect the evolution of physical characteristics in animals? What is beautiful to a frog or a peahen? In A Taste for the Beautiful, Michael Ryan delves deeply into the question of sexual attraction and argues that beauty is in the brain of the beholder.

A Taste for the Beautiful by Michael Ryan

Few people know Darwin’s life and work as well as his biographer, Janet Browne (Charles Darwin: Voyaging, Charles Darwin: The Power of Place), making her the perfect editor for The Quotable Darwin. Drawing on the full range of Darwin’s writings, including his letters to friends and family, and his private notebooks, The Quotable Darwin is an unforgettable picture of the man and his thought in his own words.

The Quotable Darwin by Janet Browne

Find these books and many more in our Biology 2017-2018 catalog.

Anurag Agrawal: Needing and eating the milkweed

AgrawalU.S. agriculture is based on ideas that make me scratch my head. We typically grow plants that are not native to North America, we grow them as annuals, and we usually only care about one product from the crop, like the tomatoes that give us ketchup and pizza.

And we don’t like weeds. Why would we? They take resources away from our crops, reduce yields more than insect pests or disease, they’re hard to get rid of, and they might give you a rash. But there are few plants more useful, easy to cultivate, and environmentally friendly than the milkweed. The milkweed takes its ill name from the sticky rubbery latex that oozes out when you break the leaves, it’s the monarch butterflies only food, and it is a native meadow plant. Milkweed has sometimes received a bad rep, and perhaps for good reason; they can be poisonous to livestock, they are hard to get rid of, and they do reduce crop yields. But what about milkweed as a crop?

AgrawalThomas Edison showed that milkweed’s milky latex could be used to make rubber. The oil pressed from the seed has industrial applications as a lubricant, and even value in the kitchen and as a skin balm. And as a specialty item, acclaimed for its hypoallergenic fibers, milkweed’s seed fluff that carries milkweed seeds in the wind, is being used to stuff pillows and blankets. Perhaps more surprising, the same fluff is highly absorbent of oils, and is now being sold in kits to clean up oil tanker spills. The fibers from milkweed stems make excellent rope and were used by Native Americans for centuries. More than two hundred years ago, the French were using American milkweed fibers Agrawalto make beautiful cloths, said to be more radiant and velvety than fine silk. And chemically, milkweeds were used medicinally by Native Americans since the dawn of civilization, with a potential for use in modern medicine.  This is a diverse plant with a lot to offer.  Why wouldn’t we cultivate this plant, not only for its stem fibers, seed oils, pillowy fluff, rubbery latex, and medicines, but also in support of the dwindling populations of monarch butterflies?

Ever since the four lowest years of monarch butterfly populations between 2012 and 2015, planting milkweeds for monarchs has been on the tips of a lot of tongues. For most insects that eat plants, however, their populations are not limited by the availability of leaves.  Instead, their predators typically keep them in check, or as in the case of monarchs, there may be constraints Agrawalduring other parts of their annual cycle. Monarchs travel through vast expanses from Mexico to Canada, tasting their way as they go. They tolerate poisons in the milkweed plant; indeed, they are dependent on milkweed as their only food source as a caterpillar. Nearly all mating, egg-laying, and milkweed-eating occurs in the United States and Canada. And each autumn monarchs travel to Mexico, some 3,000 miles, fueled only by water and flower nectar.

All parts of the monarch’s unfathomable annual migratory cycle should be observed and studied. My own research has suggested that habitat destruction in the U.S., lack of flower resources, and logging at the overwintering sites in central Mexico are all contributing to the decline of monarch butterflies. Lack of milkweed does not seem to be causing the decline of monarchs. Nonetheless, planting native milkweeds can only help the cause of conserving monarch butterflies, but it is not the only answer. And of course we humans need our corn and soy, and we love our broccoli and strawberries, so is cultivating milkweed really something to consider?

We humans, with our highly sensitive pallets, do the one thing that monarch butterflies don’t do. We cook. And the invention of cooking foods has been deemed one of the greatest advances in human evolution. Cooking certainly reduces the time spent chewing and digesting, and perhaps more importantly, cooking opens up much of the botanical world for human consumption, because heat can break down plant poisons.

AgrawalEuell Gibbons, the famed proponent of wild plant edibles in the 1970s, was a huge advocate of eating milkweed. The shoots of new stems of the eastern “common milkweed” are my personal favorite. I simply pull them up when they are about 6-8 inches tall and eat them like asparagus. Gibbons recommended pouring boiling water over the vegetables in a pot, then heating only to regain the boil, and pouring off the water before sautéing. You can pick several times and the shoots keep coming. With some preparation, the other parts of the milkweed plant can be eaten too, and enjoyed like spinach, broccoli, and okra.

At the end of summer, many insects have enjoyed the benefits of eating milkweed, especially the monarch butterfly. Any boost we could give to the monarch population may help use preserve it in perpetuity. But the real value in cultivating milkweed as a crop is that it has a lot to offer, from medicines to fibers to oils. It is native and perennial, and can be grown locally and abundantly.  Let’s give this weed a chance.

Anurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He is the author of Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution.

Agrawal

Rebecca Tansley & Craig Meade: The Pacific Ocean as you’ve never seen it before

The Pacific Ocean covers one-third of Earth’s surface—more than all of the planet’s landmasses combined. It contains half of the world’s water, hides its deepest places, and is home to some of the most dazzling creatures known to science. The companion book to the spectacular five-part series on PBS produced by Natural History New Zealand, Big Pacific breaks the boundaries between land and sea to present the Pacific Ocean and its inhabitants as you have never seen them before. Providing an unparalleled look at a diverse range of species, locations, and natural phenomena, Big Pacific is truly an epic excursion to one of the world’s last great frontiers. In our latest Q&A, author Rebecca Tansley and showrunner Craig Meade ask each other questions about the series, the book, and the majestic Pacific Ocean:

Questions from Rebecca to Craig

There have been a lot of documentaries made about the oceans and the animals that live in them. How did the Big Pacific idea come about and what new perspectives did you think this series could bring?
It started ten years ago in a late night conversation in France with some of Japan’s best wildlife filmmakers.  We realized that after a thousand years of humanity dominated by the Atlantic and its people that the next thousand years would probably be owned by the Pacific. We conjectured that if we inverted the paradigm and considered the Pacific Ocean a continent, it would already hold many of the world’s major cities: Seattle, LA, Tokyo, Shanghai, Sydney, Taipei.  So what are the natural values of this new continent, what does it say to us, and what does it mean to us? What are its emotional messages? Let’s put a flag in it, explore it and see what we discover about it. So that night we started looking for the defining stories that we should tell of the Pacific Ocean.

The book sections match the episodes of the Big Pacific show – Passionate, Voracious, Mysterious, Violent. How did you come up with these themes and decide to structure the series around them?

To matter, stories must move us, trill our emotional strings. Usually these kind of words are embedded in the undercurrent of the script. Hinted at. But the Pacific is big and bold and we thought our statements about it should be so too. It’s all those things: passionate, voracious, violent and mysterious, but it’s also many other things. So I don’t believe this journey to capture its multitude of faces is yet over. Please let me do the Ecstatic, Selfish and Uncertain shows one day as well!

I talked to crew members about some of the special moments in the series’ production, but which is the most special Big Pacific moment for you, on screen?

The Yellow eyed penguins in the Passionate episode. Less than 4000 adults remain. They are a species that may have just a decade or two left and the cinematographer captured their cold and lonely existence beautifully. It’s not a story of sorrow but one of the bird’s passionate relationship with its mate and family. Like a black and white waddling hobbit he comes home from work and wanders through the mossy forest to the cave they all share. It’s an idyllic glimpse of natural New Zealand and a rare and wonderful animal few people are ever going to see. If they disappear for good from the wild I’ve no doubt this story is the one they’ll play to teach kids what a Yellow eyed penguin once was like.

The Big Pacific series is highly entertaining but also packed with fascinating information – I learned a lot writing the book! In a world of increasing pressure on our natural environment, what is the role of natural history storytelling?

I think it’s increasingly important we do not sugar-coat the truth. We mustn’t be the blind purveyors of a dream while a nightmare plays out in the natural world. So as filmmakers there’s always a tension in what we do. I actually want to bring you a dream so you know why we must protect what we have left in the wild world – but I mustn’t let that dream lie to you and hypnotize you into believing the dream is entirely real. Because in some cases the dream is already over. Like the Yellow eyed penguin story I mentioned, I find myself handling a story as though I am preserving something already lost; instead of revealing something new I find myself working to faithfully capture the essence of what was.

Questions for Rebecca from Craig

The Pacific Ocean is many things to many people: a place, a home, a source of food, a gulf between land masses. How did writing the Big Pacific book change your sense of what the Pacific is to us?

I grew up with the Pacific literally at my front door and I’ve never been far from it for my entire life. It’s been my playground, my pastime and my place of solace. Because of this, for me as well as millions of other people like me, it’s hard to define just what the Pacific means – it just infuses our lives. This is one of the many reasons I was attracted to this project, because of the way it focuses not just on the Pacific’s natural history but on people’s relationship with it too. I hope that comes through in the book, because you can’t separate the animals or the people from the ocean they live in and around. We are, actually, in many ways defined by our place in or on the Pacific. Writing the book reinforced this view and gave me an opportunity to express it.

There are so many evocative images in the Big Pacific book, is there one that you keep on returning to?One animal that you want to meet?

Oh that’s a tough one, because I’m in love with so many of the animals and the images! I’ve always had a strong interest in whales so I find the images of the rare Blue whale captured by Big Pacific Director of Photography, the late and obviously very talented Bob Cranston, mesmerizing. But in the course of writing the book I discovered many other wonderful members of the Pacific community. Among them are the Wolf eels, whose dedication to their partner and to their brood is totally endearing. I love the images of the Firefly squid because they seem so ethereal and their lives are so fleeting, yet nature has nonetheless equipped them miraculously for their short, spectacular journey. Plus I can’t not mention the Chinese horseshoe crab, because they are such admirable survivors. I hope the whole world wakes up to the beauty and value of all the animals that live in and around not just the Pacific but all the planet’s oceans, and recognizes that they deserve their place in it for the future as much as we do.

Natural history stories at their heart are science stories – but with fur and scales. To be enjoyable and understandable they usually require simplification, but still need to be highly accurate. That sounds like a complicated dance to perform when writing, was it?

I’m a storyteller, not a scientist, but like a scientist I’m curious about the world. The process I used for Big Pacific worked well. First I read the (draft) series scripts and watched the Big Pacific footage. This meant I became intrigued with the animals first and foremost as characters, and was drawn into other aspects of the Pacific’s natural history – such as the Silver Dragon and the Ring of Fire – as stories. When I set about writing I drew on the science that was provided to me by Big Pacific researcher Nigel Dunstone. Then it was a matter of asking myself, what do I find interesting about that animal or story that others might also enjoy? What might people not know? What is dramatic about this story? Of course I also ensured I was covering off important information, such as environmental threats and conservation status, and everything I wrote was checked afterwards by Nigel and the Big Pacific team.

You’ve made some fantastic films between your writing jobs, is it hard to transition from the spoken word to the written?  Are they two different crafts?

Writing and filmmaking are related in terms of both entertaining and organizing information for an intended audience, but they do that in different ways and to a large extent employ different skill-sets. Obviously filmmaking is a collective pursuit that usually requires a team of people, whereas writing is a solitary craft. I enjoy both equally and writing/directing my own films enables me to do this. I was fortunate enough to spend time with the Big Pacific team when I selected the images for the book, and also interviewed others, so in this writing project I did get to collaborate. I would add that when I write I’m very conscious of rhythm – an aspect that’s also important to aspects of filmmaking, such as narration and editing. I’m not really musical, but I like to think that I have that sense of linguistic rhythm and flow. Perhaps that’s why I studied languages for many years!

TansleyA documentary filmmaker herself, Rebecca Tansley has previously worked at the production company that made the Big Pacific series, NHNZ. In addition to writing and directing films she has written two other internationally published books and been a contributor to national magazines and newspapers in her home country of New Zealand. Rebecca has degrees in languages, media production and law.

Craig Meade and the production team at NHNZ are some of the most successful and prolific producers of natural history programs on the planet—more than 50 wildlife shows completed in just the last four years. But after 30 years of writing and directing Craig still doesn’t class himself as a wildlife filmmaker—he’s a science guy that prefers mud, tents and mosquitoes to laboratories. When he’s not making films Craig is a deer hunter and an on-call fire fighter.

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.

Paul Strode: Teaching The Serengeti Rules

CarrollIn January of 2016 I was asked by Laura Bonetta at the Howard Hughes Medical Institute (HHMI) to write a teacher’s guide for the short film Some Animals Are More Equal than Others: Keystone Species and Trophic Cascades. At the same time, Molecular Biologist Sean B. Carroll, the HHMI Vice President of Science Education, was putting the finishing touches on his new book, The Serengeti Rules. To help expedite my research for writing the teacher’s guide for the short film, Laura sent me a pre-pub copy of the book and suggested I read Chapter Six: “Some Animals Are More Equal than Others.”

Instead of going straight to Chapter Six, I started reading from the beginning.

Before I was even halfway through the first chapter, I thought to myself, this book is going to change the way I teach. At the core of Carroll’s storytelling is the observation that everything is regulated, from molecules to megafauna. Indeed, for most of my career teaching biology I have kept my focus on Theodosius Dobzhansky’s argument that “nothing in biology makes sense except in the light of evolution.” But Carroll has now made it clear that nothing in biology also makes sense except in the light of regulation.

To make a long story short, I wrote the short film teachers guide with the help of Chapter Six in The Serengeti Rules and immediately followed that task by reviewing the book for The American Biology Teacher so that other teachers might benefit from reading the book. In my review, I argued that The Serengeti Rules “should be required reading for students in all fields of science, but especially those pursuing careers in biology education.” My review caught the attention of Carroll’s editor at Princeton University Press, Alison Kalett. Alison was curious to know if teachers like me that planned to use Carroll’s book to enhance their biology courses would find it useful if educational supplementary materials were made available… for free. Alison and I came up with a plan and I began to write.

The Serengeti Rules came out in March of 2016 and one of Carroll’s first public discussions about the book was at the annual Professional Development Conference of the National Association of Biology Teachers in Providence, Rhode Island. Several hundred teachers showed up to hear from Dr. Carroll and it was standing room only. As word got out that supplementary materials were being prepared for Carroll’s book, inquiries began to pop up on social media.

Carroll

The Educational Supplement was released in May and is a document that a teacher can use immediately in the classroom.

Carroll

The questions come in various styles and are designed to invoke classroom discussion, require students to synthesize and connect various biological concepts, get students to engage with ecological data from the published journal articles, and have students analyze and graph data that relate to what they are reading in The Serengeti Rules. For example, the question below relates to Chapter Four of The Serengeti Rules, “Fat, Feedback, and a Miracle Fungus.” The question can be used as a formative assessment question that marries real data with the nature of science and covers several components of the Advanced Placement and International Baccalaureate biology course content.

Carroll

Teachers have already begun planning to use The Serengeti Rules to enhance their courses and since the release of the supplement have expressed their gratitude that it is available and free!

Carroll

And of course, I have assigned The Serengeti Rules as summer reading for my 65 AP/IB biology students and I am looking forward to using the questions in the fall to incite discussion and enhance learning and understanding.

Thank you, Sean B. Carroll, for giving us The Serengeti Rules!

Dominic Couzens: The extraordinary (and overlooked) water shrew

water shrewAsk most people whether they have heard of a water shrew and they’ll shake their head. If you tell them that there are 1.9 million water shrews in Britain and that they have a poisonous bite, then those same people are likely to raise their eyebrows, amazed they have never heard of it. The water shrew (not a water vole or a “water rat”) manages to keep a remarkably low profile for the extraordinary creature that it is.

Shrews are the mammals that look superficially like mice—they are small, brown and furry—yet are quite unrelated to them. They are flatter-bodied than mice and don’t hop, and have long snouts that move around in a somewhat robotic, mechanical fashion as they seek food. With small eyes (they are related to the almost-blind moles) and small ears, shrews lack the features that give mice and voles an easy identity to humankind. Shrews don’t live indoors or steal our food, either; they subsist on a diet of insects and other small living things. So shrews aren’t exactly on our doorsteps, asking to be noticed.

But shrews cross our paths alright, even if we aren’t looking. They are among the most abundant of all our mammals. Aside from the water shrew, there are 42 million common shrews and 8.6 million pygmy shrews in Britain; a veritable army of voracious insect- and worm-guzzlers living at our feet. They prefer to live in long grass, dense shrubbery, and other places where it’s easy to hide.

And, of course, they choose the waterside, too. The water shrew, the largest and best-turned out of our three common species, with its smart white underside contrasting with business-suit-black above, is the most aquatic of the three. Although it is perfectly at home in undergrowth away from water, its signature hunting method is to immerse in still or slow-flowing water, diving down to depths of 2m or more for up to 30 seconds, to snap up crustaceans, insect larvae, snails, worms, and small vertebrates such as newts, frogs, and fish. It is the only British mammal adapted to tap into this underwater niche of small freshwater life.

As it happens, the water shrew can also tackle prey larger than itself, by means of its remarkable venomous saliva, which immobilizes frogs or fish. The venom is a neurotoxin, causing paralysis and disorders of the blood and respiratory system. It is toxic enough to be a very unpleasant skin irritatant in humans that may take days to subside.

The water shrew has several adaptations to its preferred aquatic lifestyle. The surface of each foot is fringed with stiff hairs, increasing the area of the limb, like a flipper, allowing this mite to swim efficiently. The tail also has stiff hairs on the underside, making it act like a rudder, for steering. The hairs on the body also trap a layer of air, keeping the shrew warm underwater, even in the middle of winter.

Shrews, although small, don’t hibernate. Instead they must remain active throughout the winter, requiring a meal at least every two hours, day and night. It isn’t easy to sustain, and many shrews don’t survive. In fact, almost every adult dies after a single breeding season, meaning that only the juveniles born during the spring and summer survive to the next season—just another extraordinary aspect of this overlooked animal’s life.

Dominic Couzens is one of Britain’s best-known wildlife writers. His work appears in numerous magazines, including BBC Wildlife and BBC Countryfile, and his books include Secret Lives of Garden Wildlife and Britain’s Mammals: A Field Guide to the Mammals of Britain and Ireland.

Peter Ungar on Evolution’s Bite

UngarWe carry in our mouths the legacy of our evolution. Our teeth are like living fossils that can be studied and compared to those of our ancestors to teach us how we became human. In Evolution’s Bite, noted paleoanthropologist Peter Ungar brings together for the first time cutting-edge advances in understanding human evolution and climate change with new approaches to uncovering dietary clues from fossil teeth to present a remarkable investigation into the ways that teeth—their shape, chemistry, and wear—reveal how we came to be. Ungar recently took the time to answer some questions about his new book.

Why do paleontologists care so much about teeth? What makes them so special?

PSU: Paleontologists care about teeth because oftentimes, that’s all we’ve got of extinct species to work out details of life in the past. Teeth are essentially ‘ready-made fossils,’ about 96% mineral, so they survive the ages much better than other parts of the body. They are special because they come into direct contact with food, and can provide a bridge to understanding diet in the past. We can tease out the details by studying their size, shape, structure, wear, and chemistry. Teeth connect us to our ancestors, and them to their worlds. I like to think of nature as a giant buffet of sorts. I imagine animals bellying up to the sneeze guard on this biospheric buffet with empty plate in hand. Teeth can teach us about the choices they make; and it’s those choices that help define a species’ place in nature. As the old adage goes, you are what you eat. Teeth are important because they can help us understand relationships between animals in the past and the worlds around them, and about their—and our—evolution.

Why do we have so many problems with our teeth today? Why do we get cavities, require braces, and have impacted wisdom teeth?

PSU: Think about how extraordinary your teeth are. They have to break food, without being broken themselves, up to millions of times over your lifetime. And they have to do it built from the very same raw materials as the foods you are eating. Nature is truly an inspired engineer, and it’s remarkable they last as long and function as well as they do. But they’re not perfect. Most of us today get cavities, and many of us have crooked front teeth, and impacted wisdom teeth. This is largely because of our diets. We eat mostly soft foods, loaded with highly-processed carbohydrates, especially refined sugars. Cavities form by erosion from acids produced by plaque bacteria. Feeding those bacteria diets high in carbohydrates, especially sugars, means more cavities. Also, when we eat soft foods as children, we don’t exercise our jaws enough to stimulate the growth they need to make room for all our teeth. The result is crowded lower incisors, uppers that jut out over the lowers in the front of the mouth, and impacted third molars in the back. It’s not that our teeth are too big for our jaws, it’s that our jaws don’t grow long enough to accommodate all our teeth. Most traditional foragers that eat tougher or harder foods have longer jaws, and so don’t suffer the sorts of orthodontic problems the rest of us have.

Do other species have these problems? If not, why are we so different?

PSU: I’ve seen cavities and evidence for gum disease in some non-human primates, particularly in species that eat a lot of fleshy, sugary fruit, but they’re much rarer than in us. There are very few early human fossils that provide evidence of dental disease in our distant past either. Again, it seems to be a mismatch between our diets today, and the foods that we evolved to eat. Our teeth are not designed for hamburgers and French fries, nor to be bathed in milkshake. If you want to see evidence of that mismatch, just smile and look in a mirror.

What was your motivation for writing a popular science book?

PSU: My PhD dissertation was 654 pages, mostly focused on a quarter of a square millimeter of the surface of some incisor teeth. Most academics are so narrow in their research focus that it can be difficult to see the forest for the trees. I wrote this book to give myself the big picture, to give me an appreciation of the larger context into which my own work fits. Also, no more than half a dozen people actually read my dissertation cover to cover, and that includes my mother. Academics often feel like they’re speaking, but no one is listening. I wanted to reach a larger audience. This book at first glance seems to be about teeth – but it’s really about the biospheric buffet, and how environmental change over deep time swapped out items and choices available to our distant ancestors. The take-home message is that large-scale climate swings winnowed out the pickier eaters among us, and drove our evolution. Teeth are our window through which to see it. The most important message here is that climate changes, and species have to change to accommodate or die. That’s why we’re here. It’s a timely, important lesson.

As a scientist who has spent the last three decades studying evidence for the evolution of human diet, what do you think of today’s “Paleolithic diet” trend? And what was the ancestral human diet, anyway?

PSU: I’m not a fan. I like pizza and bagels too much. Still, there’s little doubt that our ancestors did not eat such things; so it makes sense that a discordance between the foods we evolved to consume and what we fuel ourselves with today can wreak havoc on our bodies. Try putting diesel in a car built to run on regular gasoline (actually, don’t). And people do lose weight when they cut refined carbohydrates and processed sugars from their diets. We could well benefit from eating more like our Stone Age ancestors, with menus like those in some popular diet books—you know, spinach salads with avocado, walnuts, diced turkey and the like. I am not a nutritionist, and cannot speak with authority about the nutritional costs of benefits of Paleolithic diets—but I can address their evolutionary underpinnings. Think about it this way. Any diet that drains the body of fat reserves means not meeting daily caloric needs. It is difficult to believe that nature would select for us to eat only foods that don’t provide the nutrients required to maintain the body. In fact, the whole idea of the Paleolithic diet is problematic. Even if we could (and we can’t) reconstruct the glycemic load, fatty acid, macro- and micronutrient composition, acid/base balance, sodium/potassium ratio, and fiber content of foods eaten at a moment in time in the past, the information would be meaningless for planning a menu. All these nutrients varied with food availability over space and time, as items on the biospheric buffet table were swapped in and out, so focusing on a single point in our evolution is futile. We’ve been a work in progress for millions of years. What was the ancestral human diet? The question itself makes no sense.

Peter S. Ungar is Distinguished Professor and director of the Environmental Dynamics Program at the University of Arkansas. He is the author of Teeth: A Very Short IntroductionMammal Teeth: Origin, Evolution, and Diversity and Evolution’s Bite: A Story of Teeth, Diet, and Human Origins.

A giveaway for the Kentucky Derby

Horses of the World by Élise Rousseau and illustrated by Yann Le Bris is a beautiful, detailed guide to the world’s horses. It covers, for the first time ever, all 570 breeds of domestic and extant wild horses, including hybrids between the two and between domestic breeds and other equids, such as zebras. In honor of the Kentucky Derby coming up on Saturday, May 6, we’re giving away five copies via Goodreads. Enter for a chance to win this must-have guide for all the horse-lovers out there.

 

horses

 

 

Élise Rousseau is a freelance writer and author of a number of adult and children’s books on horses. She is an avid equestrian and has traveled all over the world to document rare breeds. Yann Le Bris has been a professional artist for eighteen years and has illustrated numerous books.

 

Anurag Agrawal: Monarchs vs. Milkweed

by Anurag Agrawal

Coevolution is a special kind of evolution. And monarchs and milkweeds exemplify this special process. In particular, what makes coevolution special is reciprocity. In other words, coevolution is one species that evolves in response to the other, and the other species evolves in response to the first. Thus, it is a back-and-forth that has the potential to spiral out of control. In some arms races, the two organisms both benefit, such as that between some pollinators and flowering plants. But coevolution is more common among antagonists, like predators and their prey.

When biologists first described coevolution, they likened it to an arms race. An arms race, such as that between political entities, occurs when two nations reciprocally increase their armament in response to each other. So how does an arms race between monarchs and milkweeds, or between cats and mice, or between lions and wildebeest, or between plants and their pathogenic fungi, proceed? When coevolution occurs, it proceeds with “defense” and “counter defense.” And one of the few rules of coevolution is that for every defense that a plant or prey mounts, the predator mounts a counter defense, or an exploitative strategy to overcome the defense.

Once a monarch butterfly lays an egg on a milkweed plant, the natural history of coevolution unfolds. For every defense that the plant mounts, milkweed mounts a counter defense. Once the caterpillar hatches, it must contend with a bed of dense hairs that are a barrier to consumption of the leaf. But monarchs are patient, and have coevolved with the milkweed. So their first strategy is to shave that bed of hairs such that the caterpillar has access to the leaves that lie beneath.

Agrawal

For every defense there’s a counter defense. But next, when the monarch caterpillar sinks its mandibles into the milkweed leaf, it encounters a sticky, poisonous liquid called latex. In this video we will see how the monarch caterpillar deactivates the latex bomb that the milkweed puts forward.

And so the arms race continues, with reciprocal natural selection resulting in coevolution between monarchs and milkweeds. In my book, Monarchs and Milkweed, I outline the third level of defense and counter defense between these two enemies. Milkweed next mounts a remarkable and highly toxic defense chemical called a cardiac glycoside. But, yes, again the Monarch has evolved the means to not only not be poisoned by the cardiac glycoside, but to sequester it away and put it to work in defense of the Monarch itself from its enemies, such as predatory birds. For more on the Monarch – Milkweed arms race see this video, filmed in Ithaca, New York outside of Cornell University where we conduct our research.

AgrawalAnurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He is the author of Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution.

Celebration of Science: A reading list

This Earth Day 2017, Princeton University Press is celebrating science in all its forms. From ecology to psychology, astronomy to earth sciences, we are proud to publish books at the highest standards of scholarship, bringing the best work of scientists to a global audience. We all benefit when scientists are given the space to conduct their research and push the boundaries of the human store of knowledge further. Read on for a list of essential reading from some of the esteemed scientists who have published with Princeton University Press.

The Usefulness of Useless Knowledge
Abraham Flexner and Robbert Dijkgraaf

Use

The Serengeti Rules
Sean B. Carroll

Carroll

Honeybee Democracy
Thomas D. Seeley

Seeley

Silent Sparks
Sara Lewis

Lewis

Where the River Flows
Sean W. Fleming

Fleming

How to Clone a Mammoth
Beth Shapiro

Shapiro

The Future of the Brain
Gary Marcus & Jeremy Freeman

Brain

Searching for the Oldest Stars
Anna Frebel

Frebel

Climate Shock
Gernot Wagner & Martin L. Weitzman

Climate

Welcome to the Universe
Neil DeGrasse Tyson, Michael A. Strauss, and J. Richard Gott

Universe

The New Ecology
Oswald J. Schmitz

Schmitz