Evolution’s Bite

Short Talks From The Hill is a podcast highlighting research and scholarly work across the University of Arkansas campus. Each segment features a university researcher discussing his or her work.

Delani Bartlette: Hello and welcome to Short Talks from the Hill, a podcast from the University of Arkansas.  My name is Delani Bartlette. On this episode, Peter Ungar, Distinguished Professor of Anthropology and director of the Environmental Dynamics Program will read excerpts from his new book Evolution’s Bite, which presents his research with fossil hominid or human ancestor teeth and the clues they give us about our ancestor’s diets. Welcome.

Peter Ungar: Thank you.

DB: So, you’ve got some information for us here.  You’ve got a piece, talking a little bit about how teeth are used. Do you want to read us about that a little?

PU: Sure. This is from chapter two. “You’re not supposed to do that” I told my wife, Diane as I transcribed field notes by the light of our kerosene lamp at Ketambe, our research station in Indonesia’s Gunung Leuser National Park. We had just arrived in the rain forest only a week before and I had just finished following Guhantara, a group of small tail Macaques that live in a small patch of rain forest along the left bank of the Alos River.  Page after page of dietary observations. It was leaves, leaves and more leaves, but they have the teeth of a fruit-eater.  Their incisors are large, for peeling husks, and their molars have short crests and rounded cusps for pulping food flesh.  The common name for their biological sub- family is even “fruit eating monkeys.”  Clearly these Macaques hadn’t read the literature on tooth form and function.  I realized that night that it’s one thing to study teeth in the laboratory and another entirely to see how they’re actually used by primates in their natural habitat.  Both are important.  The take-home message is, as I learned during my first weeks at Ketambe, there’s more to food choice than teeth.  Yes, teeth are important.  They give an animal access to food that would otherwise off their table.  But primates also have to worry about getting the right mix of nutrients to meet their nutritional needs.  Contend with competitors and avoid predators while feeding.  Then there’s the issue of availability.  Potential appear and disappear in the forest like daily specials at the corner deli.

DB: That’s a good point.  From that you also talk about looking at the fossil teeth. Do you want to tell us a little bit about that?

PU: Sure, I’ll read a small section from chapter 3. It gives you an idea what it’s like to study fossil teeth. Some of the most important fossils in the world used to be kept in a small vault room at the University of Witwatersrand Medical School in Johannesburg.  The former dean of the faculty and my own academic grandfather, Phillip Tobias, used to call the collection an embarrassment of riches.  The vault door opened into a modest laboratory, a room lined by shelves of old plaster busts, the faces of human ancestors found thorough Africa and Asia, and casts of their teeth and bones.  The replicas were there so the researchers could compare them with the precious original specimens housed in the collections.  There was a large table in the center of the room covered with lime green felt.  That’s where guests worked.  I remember the first time I visited.  I couldn’t wait to see and touch the actual remains of our distant ancestors, ones who lived millions of years ago.  I’d read so much about them that each specimen was like a living, breathing being to me.  The custodian of the vault brought out a wooden tray cradling half a dozen specimens; teeth and jaws of Australopithecus.  He laid it down on that lime green felt.  I’d studied for years and flown half way around the world for this moment.  I was expecting it to be humbling and awe-inspiring, coming face-to-face with those fossils.  But it wasn’t; it was anti-climactic.  They were just teeth.  Cold, lifeless teeth.  I guess I had expected them to exude some sort of fundamental essence; some wisdom that told me who they were, what their lives were like and how they were related to me.  But they didn’t.  Then it hit me.  Everything I had learned about Australopithecus, its lifestyle and relationships, had been teased from those teeth and bones by the generations of researchers who came before.  The fossils themselves weren’t humbling.  They weren’t wise.  The scientists who gave them meaning were. 

DB: That’s really very evocative. I like that piece. So now your one of those scientists and your work has been looking at those teeth to learn more and to tell us more about the diets of our ancestors. That’s a really big topic right now as I’m sure you know with the Paleo-diet. It’s ranked really highly on Google searches, but you’ve said in your work that you’re not a fan of the Paleo-diet. You even in your book give some statistics that maybe it’s not the best diet, as far as nutritionally. But you have kind of a different perspective on why you’re not a fan.  You want to tell us about that?

PU: Sure. I’ll do just one more short reading from the final chapter of the book. And that gives my perspective on the Paleo-diet or the Paleolithic diet actually. Paleo-diet refers to a very specific trademark diet. The Paleolithic diet is a myth. Food choice is as much about what’s available to be eaten as it is about what a species evolved to eat. Just as foods appear and disappear from the forest throughout the year, dishes have put out and taken away as our world has changed over time.  That change has driven our evolution. Even if we could, and we can’t reconstruct the nutrient content of foods eaten by a specific hominin, the information would be meaningless for planning a menu based on our ancestral diet. Because our world was ever-changing, so too was the diet of our ancestors. Focus on our ancestor at one point in our evolution would be futile. We’re a work in progress. What was the ancestral human diet? The question itself makes no sense.   

DB: That’s excellent, thank you so much for coming in and reading this.  The book is Evolution’s Bite. It’s been released this month?

PU: Correct.

DB: By Princeton University Press. Thank you.

DB: Music for Short Talks from the Hill was written and performed by Ben Harris, guitar instructor at the University of Arkansas. For more information and additional podcasts, go to KUAF.com or ResearchFrontiers.uark.edu, the home of research news at the University of Arkansas.