>> I'm delighted to be here today with Professor Emeritus Alan Mann. He's a Professor of Anthropology at Princeton University and has a fascinating career studying the Neanderthals and early humans. Well, my first question to you, Allan is, what got you interested in working on early humans and Neanderthals? I have always been interested in my roots and where I came from, where my family came from, where the populations of Europe, Africa, Asia, and the Americas came from. It is only a short drum from looking at your grandparents, great-grandparents, great-great-grandparents to go back 1,000 or 2,000 generations. I began to wonder about how we became human. What were the mechanisms in our evolutionary history that produced peoples like ourselves? As I got into this, I began to look at the Neanderthals, these peoples who lived in Europe and the Middle East all the way into almost Asia, who seemingly became extinct 30,000 years ago. They didn't look like us. They had big brow ridges, they had no chin, and for very long time, they were thought of as being sub-human. I became interested in them to understand just exactly what it means for a people not to look like modern humans and yet apparently to act, behave, and adapt to the environment exactly like ourselves. So I got interested in that. From there, of course, I began to wonder what they ate and diet became- That was my next question. Go ahead. Diet became a central issue because the Neanderthals lived in Europe during the last glacial period. During that time, the life zones were distinctly south of where they are. So that for example, today, where you have the tundra in the North of Scandinavia, that environment was in central France during the glacial times. Sites that have Neanderthal occupation showed just an enormous number of reindeer bones. They are seemingly or extremely efficient hunters. For a very long time that plus other evidence had suggested to many people, including most anthropologists that humans had evolved as meat eaters, that meat was the central part of any diet. Anthropologists, and psychologists, and many others who looked at these issues, including nutritionists, looked at our background as that of meat eaters. Is that correct? Well, that's a very good question. We're beginning to see that the earliest evidence of our earliest ancestors, just after our line separated from the line that will eventually evolve into modern chimpanzees, they are our close relatives. Of course, they're not ancestors at all. That these early creatures apparently were consuming mainly vegetation, and it was apparently a fairly wide array of vegetation. They were also apparently opportunistic meat eaters. I should point out that chimpanzees, again our closest living relatives, but we use them to get some indirect understanding of what our ancestors were like. Chimpanzees are also opportunistic meat eaters. In fact, chimpanzee males have been known and observed especially by Jane Goodall and her colleagues to actively hunt and kill a variety of animals. So meat eating is certainly part of our heritage. It would seem to be a common inheritance from the common ancestor of chimpanzees and humans, but just how much meat eating is in our background and just how important was it in the context of eating other kinds of foods, especially vegetables and fruits. Obviously, no human ate any dairy or perhaps not many grains before the origin of agriculture and animal domestication. That only took place 12, 13, 14,000 years ago. So we're talking about a diet that may have been predominantly meat or it may have been more omnivorously based with a lot of fruits, and vegetables, and things like that. I should point out that early on I became very interested in insect eating because insects are generally not part of the Western diet. People really shirk at the idea of putting something like a cockroach in their mouths. The fact of the matter is, of course, that we all eat insects in one degree or another. If you look at today, the US Department of Agriculture's rules on what they call incidental insect decidua in terms of ground grains, or sugar, or other things, they allow a certain amount because it's impossible to keep them out. Well, look at lobsters. Lobsters are insects of the sea. I mean, one time they were considered vermin and fed to prisoners, and then in the 20th century, somebody came up with a brilliant marketing scheme to make them a gourmet food. Yes. Now lobsters are very popular, but one could argue that they are the insects of the sea. Yes, and shrimp. Shrimp as well. People eat clams. People eat many foods that might be considered disgusting by others. It is very interesting that as I looked into insect eating, I discovered that in the Old Testament, in the Book of Leviticus, where food prohibitions are listed for reverend Jews as well as I think many Muslims. In Leviticus, there are all kinds of food prohibitions including eating animals that have odd toes, like pigs. Well, pigs have four toes. But that's something else, but horses and camels. But in Leviticus, it is specifically noted that grasshoppers, locusts, and katydids are kosher. So they must have had an important role to play in at least the ancestry of Middle Eastern peoples. So one wonders about just how important they are. Of course, they are an incredibly wonderful source of many nutrients. I can't say that I'm overly fond of insects, but I will in fact promote it to anybody who wants to eat them. I give them my blessings. Now we've heard a lot about the Paleo diet as the perfect diet for humans to eat. Given what you've discussed about early humans, do you think the Paleo diet is the right choice for the people to consume? What do you think? I have great deal of difficulty in working that out because I really don't think that there is a single optimal diet for humans. Because when you look around the world, you see just incredibly broader array of foods that people eat from the peoples of the North. Like the Inuit or the Saami of Northern Scandinavia, they eat a predominantly meat-based diet. In other parts of the world, vegetation is the primary source of nutrition. So we vary all over the lot. But here are a couple of problems that I see. Number 1, in most of the world, after weaning, people lose their ability to digest the sugar in milk and dairy products. This inability to digest, which is common almost throughout Asia and in many peoples and the rest of the world, that suggests that the introduction of dairy products after animal domestication late in our evolutionary history may, in fact, have not produced an evolutionary change that is worldwide, so that there are people who get sick, get nauseous, have diarrhea, and all kinds of problems eating. Foods that have the milk sugar, lactose. So that is one problem. The other problem is there are large numbers, although I'm not sure just exactly how much because this is a cultural problem, many, many people have an inability to digest the grain protein, gluten. Today when you go to an American supermarket, there are whole aisles of gluten free products. How much of that is based on a genuine inability to digest gluten or it is something that people feel better in not doing even though they don't have any particular problem. This has been studied and there are some interesting explanations about why people who don't have an inability to digest this protein nevertheless, eat gluten-free foods. Well, we've had agriculture for 10,000 years, wouldn't you think that we would have developed the ability to digest gluten or milk in that period of time of agriculture? I mean, it's surprising that humans, since they routinely eat it, have problems digesting it. Yes. But not all grains have gluten. Rice does not have gluten, corn does not have gluten. It's primarily wheat that has gluten, barley I think as well. So these are particular grains that have a very limited distribution. I see. People in East Asia who grew up in the rice eating area have no problem. The same thing in North America and South America. So these are specific things. Why so many Europeans have assumed gluten problems is something that I don't understand. So that suggests to me that maybe there really is something to the paleo diet that people would be better off not eating the specific foods that came about through animal domestication and agriculture. That's one problem. The real problem is, as far as I can see, when you talk to people who follow the paleo diet, they are overwhelmingly focused on meat. The idea being the meat eating was a crucial part of our evolutionary history, and that you can be very healthy eating as much meat as you can. Well, there are a lot of problems with that. Of course, in our society when we're eating domestic animals who are fed a wide variety of foods to fatten them up, and up until very, very recently, the standards for meat quality from standard to prime and choice were based on marbling. That is, the amount of fat that was found between the muscles, and that fat probably is not terrifically good for you dietarily. So there is a difference there. Most wild animals have almost none of that particular fat and many, many of the other animals that people eat and ate in the past, like insects and reptiles, have almost none of that fat as well. So there is a problem with that. I think a paleo diet that would de-emphasize meat and emphasize again a very broad array of vegetables and fruits would, I think be, in my estimation, a really good choice. I know that modern gatherers or hunters, there are none left now. But over the past century, many were studied in their original habitat in Asia, especially in Africa, but also in the Amazon. What we found was that their diet was seasonally amazingly diverse, and that they were eating dozens and dozens of different vegetables and fruits over a yearly round. Now, that variety provided them with not only a range of nutrients, but an enormous variety of those nutrients, including now the micronutrients that we know are crucial for our good health. The microbes as well. The microbes as well. Exactly. Right. Now, the early humans eating the paleo diet, did they cook their food or were they eating mostly raw food? When did people start cooking their food? Because cooking seems to increase the nutritional value of food too. Isn't that correct? It is. We are not completely aware of when dietary items were cooked. We have evidence at least half a million and maybe three-quarters of a million years ago of the presence of fires and pieces of bone that were in fact showing the charring of cooking or roasting. But beyond that, there are suggestions that the use of fire and therefore perhaps cooking goes back more than a million years. But certainly, there's a site in the Middle East where by 700,000, there apparently was very good evidence of fire and we would think then fire played a role in food preparation. Was that with early humans and Neanderthals or just early humans? Neanderthals were very well able to make fire and virtually all of their sites, we have hearths where we find bird bone and other kinds of things like that. So it's clear that they were cooking their food. Whether in fact, they charred, boiled them, or whether they ate them rare or raw. Neanderthals are not around to tell us whether they liked their meat medium rare. Sure. Well, couldn't you also look at the fossil record, the teeth, and be able to tell what people were eating by looking at that, for example? The teeth are remarkably able to tell us lots about food. For one thing, when you eat foods that have some grit in them, they leave microscopic scratches on the chewing surface of the teeth. These can be interpreted as evidence for particular kinds of foods. The problem with that is that these scratches are so indistinct. We use scanning electron microscopy to see them, but almost always the scratches represent the last foods that the individual ate. So seasonal changes, perhaps in other environments would not be in fact preserve that way. We can in fact look at stable carbon isotopes to see approximately what kinds of foods, because the carbon isotopes differ whether you're eating meat, or shellfish, or marine foods, or vegetation. So that can be a help as well. There are many other kinds of very sophisticated tests that can be made. For example, to understand whether, for example, in Neanderthals or even earlier creatures, were seasonal users of different environments. That is, they would be someplace in the dry season and another place in the wet season or summer and winter. There is in fact the use of stable isotopes of the elements strontium, because strontium is in fact differentially found in the environment so that if you find that they have a large, a high strontium content, now, strontium is not a necessary ingredient and we don't need it nutritionally. But strontium is so much like calcium that when you have strontium and you die, it is differentially incorporated into your bone so that you find it as part of the bony structure. But strontium is differentially distributed in the environment, so that if you look at a site where we find fossil bones and you analyze the strontium content, and you find that the environment that the site is in has virtually no environmental strontium, that indicates that these people either grew up in some other environment or moved regularly. So that helps us a little bit. Then there is right now the use of taking samples of calculus, which are bony or hard tissues that are adhering to the teeth. These incorporate all kinds wonderful things. For example, they incorporate seeds, they incorporate pollen, which is from plants, and they incorporate a very bizarre silica crystal called a phytolith. Now, isn't this the stuff that the dentist scrapes off your teeth when they cleanse it? Yes, it is. So the early humans didn't get to go to a dentist. So there was just build up on their teeth during their lifetime, is that right? Yeah. Well, there's some bizarre things on a couple of Neanderthal teeth. There are grooves between back teeth, and a number of people have in fact interpreted those as toothpick marks. Really? I have to say, if I might, I'm taking that with a grain of something, maybe a phytolith. Okay. So by looking at that then, can you tell what meat that they were eating? Were they eating large carnivorous animals or were they eating like antelope or something easier to hunt, for example? I would have to say, and this is one of the problems we have, that the Neanderthals weren't stupid. They were surrounded in their environment by some really fearsome animals. They were in glacial age Europe. There were these cave hyenas, which were a third larger than modern hyenas and probably really scary. There were cave lions, which were about a third larger than modern African lions. Wow. There were woolly rhinoceros, there were mammoths, there were an enormous number of fearsome animals. Up until about 20,000 years ago, there were also cave bears. Cave bears, I have seen their skulls in archaeological sites, and I must say, they are a really, really fearsome creatures. But you know in many reconstructions of our ancestors, you see them spearing a woolly rhinoceros or fighting a mammoth or grasping and wrestling with a cave bears. That's our imagination because they weren't stupid and anytime they wanted to mix up with those animals, was a really good way for them to fulfill the natural selection of Darwin, right? Yeah. So they were most likely not hunting those animals. Do you think they were scavengers? Were they looking for animals that were already killed or were they actually going out and catching their own? That's another very interesting question because up until very recently, the earliest meat eaters in our very early human evolution, long before the Neanderthals, a couple of million years ago, we begin to find bones with scratch marks on them. This represents the beginning of stone tool use as well. It was thought that maybe they were not hunting animals but scavenging animal remains that were killed by predators. This is possible but then people began to wonder, "Well, if they waited for the predators and the scavengers like hyenas to finish with them, the tissue on these dead animals would be putrid. Could they eat it without getting really sick?" There are, as far as we know, no primates that can eat putrid meat without getting really sick. The bacteria involved would be limiting. However, some recent research has suggested that humans can eat spoiled meat without too many difficulties. So maybe scavenging was the way it started. Again, chimpanzees will eat meat. In fact, when a chimpanzee and almost always males, not always, but almost always males who hunt and they cooperatively hunt and they will kill an animal like a monkey or a small antelope and they will begin to pull it apart and they will eat it together. Females and young will come over and sit almost in the mouth of the males eating the meat and beg for meat and sometimes they will get some. Chimpanzees don't share food. So this is something that is looked at as begging. But humans share food, right? Yes. This prompted me a while ago to consider one of the most wonderful aspects of human food consumption. That is, I think alone amongst all our close relatives, we bring food back to a common location. One archaeologist called it a homebase. We share food socially and we sit around together and we share the food and we eat together. No other animal does that. No other primate or any other animal? Well, the Cape hunting dogs do but no other primates. What about lions? The lion prides, don't they share food? Yes, but they don't bring it back anywhere. They eat it where they killed the prey. Oh I see. Really, so humans are unique in that, bringing the food back. Well, I don't know about other mammals, but certainly amongst primates, this is the case. Okay. So eating and sharing food has become a dramatic social occasion, where social cohesion and interactions become an important part of eating. Cause today, with our particular way of life, it has become very difficult to sit down with a family without watching the news on television and not talking. But this was and is virtually universal amongst all human populations except our advanced society, where almost always we've done away with it. But again of course, we have remnants of this. We have feasts. Thanksgiving is an honored feast in the United States and it is in fact a wonderful evolutionary part of our being. It is something that we do and we look forward to it. It's a joyous occasion. So eating is a very important part of human society and certainly there doesn't seem to be a perfect human diet. Diets seem to vary from culture to culture. Yes. But it appears that meat is a part of it. Now, certainly there are cultures where vegetarianism predominates for perhaps religious reasons. People have advocated that in order to have a sustainable future that humans should become all vegetarian. Do you think that is a realistic recommendation or do you think that would go against human nature if everyone were to become vegetarian? I don't know. I can't answer that question because I tried to be a vegetarian, but every couple of months I get this terrible meat urge and I start thinking about steaks. I eat one and then I go back to being a vegetarian and feeling really good about myself and looking down on everybody who keeps eating hamburgers. But the fact of the matter is, that I don't think we can give that up. Obviously, one of the problems is that raising cattle, raising pigs, raising sheep has an enormous price to pay in terms of climate change. An enormous amount of land is given over to cattle raising. Ecological destruction, environmental destruction, it certainly has an adverse impact on the planet's resources. The challenge then is, how do we provide meat for the world's population in an environmentally sustainable way? There are always insects. With that, thank you so much. You are very welcome. It was a pleasure. I'm not recommending you eat insects because I can't stomach them. But I suspect that in the future, it will be a basis for insect eating because the raising of them is ecologically, extraordinarily efficient. Yeah, and with that, thank you so much for watching this interview and I look forward to seeing you at our next class discussion.
