An a-maize-ing find: Archaeologist examines teeth to uncover mysterious Oneota agriculture shift

Robert Jeske, an archaeologist and professor of anthropology at UWM, knows that our teeth tell a story: What we eat, our overall health, and the kinds of crops we cultivate. His most recent paper details how his coauthors and he used dental remains to uncover the agriculture trends and diet of Wisconsin’s Oneota settlements, groupings of Native Americans who lived in clusters around the state more than a thousand years ago.

His research adds evidence to a surprising development in history: Around 1000 AD, Native Americans made a drastic shift in their diets to include more maize, and no one knows why.

Jeske sat down to talk about his research, which was published in the American Journal of Physical Anthropology earlier this year.

Robert Jeske

What was the main focus of your research?

The basic idea is that people who live in different environments, you might suspect, have different ways of making a living. We’ve been looking at how people began to use maize agriculture in Wisconsin. Many researchers assumed that you’d have a lot more maize down south than you would up north. In between here and Oshkosh is a transitional area where we go from savannah and prairie and mixed forest to more of a forested environment. That forest goes from a dry forest up to the wet forest that you see in northern Wisconsin.

We thought maybe there would be difference between how much agriculture people south of that transition would do as opposed to people north. When we looked at that, it turns out that probably not. Based on the dental characteristics we see from people south and north of that line, they seem to be engaging in agriculture at about the same rates.

So, the assumption was that people in these separate locations would have different agricultural practices because of their different environments?

Maize is a Mexican domesticate. We assume that it took time to spread from the south up to the north. Now what we’re finding is that that doesn’t appear to be the case. In fact, the amount of maize that people ate switched at about AD 1000 from being a relatively small part of the diet – probably less than 25 percent around 800 AD – to being more than 50 percent of the diet by 1100-1200.

And everybody, throughout the Midwest and the Great Lakes, appears to switch over at the same time, regardless of the actual environment that they’re in. Whether you’re down in the Ohio River Valley, which is much warmer than here, or up in the Fox Valley, which is much colder than here, or you’re out in Lake Koshkonong or down in northern Illinois, everybody seems to switch at about the same time.

And we can tell this because we look at their teeth.

How does looking at teeth tell you people made a huge shift in their diets to maize?

If you go back a thousand years and look at teeth, you’ll see they’re ground flat because they tend to have a fair amount of grit in their diet, but they tend to be very healthy. And you don’t have much in the way of caries or cavities.

After AD 1000, you get teeth falling out. You get abscesses. And you get great big cavities in large numbers of teeth. The cavity per tooth count goes way up. And it’s because of a sudden switch to maize as the major food source in the diet.

What is it about maize that is so bad for your teeth?

Maize is a carbohydrate. It’s sticky, so it sticks to your teeth. That high starch and high carbohydrate concentration turns into sugar. That sugar feeds microbes and the microbes produce acid that eats off the enamel of your teeth and allows for infection.

If you want to see it in action, take a plain cracker and put it your mouth. If you let it sit for a few minutes, you’ll begin to taste sugar. That’s because your mouth is turning the carbohydrates from starch into sugar.

Students of UWM archaeologist Robert Jeske work in an excavation of an Oneota settlement near Lake Koshkonong. Jeske studies Wisconsin’s Native Americans and recently discovered that groups across Wisconsin ate and cultivated maize at similar rates, despite variations in climate and geography. Photo courtesy of Robert Jeske.

I’m picturing you as a forensic dentist. How did you conduct your research?

In my case, we looked at notes and photographs from the teeth we’ve come across during my research at agricultural villages near Lake Koshkonong. We don’t remove human remains of Native Americans from the sites we’ve been working on at Lake Koshkonong, but record them in place if we encounter them in our excavations. One of my coauthors, Jordan Karsten at UW-Oshkosh, examined skeletons in museums around Oshkosh and Green Bay. He and a research assistant looked and physically counted each individual tooth.

Adults have 32 individual teeth. Quite often, not all of the teeth are there because they fall out. That’s a bad sign. With agriculturalists, you’ll find even with relatively young adults, there will be teeth that are missing. You can look at pre-mortem tooth loss. You can look at cavities. And you can look at the bone itself, where the tooth meets the socket. That occlusal area often shows signs of infection.

Why is it important that we know what people in Wisconsin were eating 1,000 years ago?

I’m interested in Native Americans of roughly 800 years ago. To give you a full description of what their life was like, we have to look at a whole multitude of things. We talk about their ceramic technology, their stone tool technology, the kind of work they did with antler and bone, and the kind of homes they built.

But probably the most important of all and the most basic to everything is what did they eat? If you want to know something about a person, their diet is one of the most foundational things you can know about them.

It’s really telling when you get something like what happened in AD 1000 when people made this switch. What would have happened to have made people who are living a particular lifestyle for a long time, who had known about maize for a thousand years already but didn’t use it much, suddenly doubledown on this particular food source?

That’s a burning question that you’ve got to answer. People don’t do that for no reason. We haven’t figured that out.

Admittedly knowing nothing about archaeology or this time period, my money would be on the blight of another staple crop.

It could be, but we just don’t have much evidence for that.

My money is on a religious revival movement. I think that there was a movement of people and ideas that went from east to west across the Great Lakes that was connected to maize consumption, and production of a new kind of pottery vessel that symbolized something that was connected to the use of maize.

That’s very vague, but it’s the closest I can come. There really doesn’t seem to be a very good environmental explanation for it at all.

Is this the next great mystery in archaeology?

The next great mystery is to see about farther north. There are contemporaneous populations in the same time period that live from Green Bay and north. They’ve got some interesting sites that look to be agriculture in the middle of the forest. They appear to be growing corn up in the northern forests.

We haven’t got it quantified yet, but if it quantifies to about the same use of maize at about the same time period, but that far north? That, I think, will be an interesting way to think about corn and how it came to be some important to Native American populations. It really wasn’t important back, say, in AD 500, in the northeastern United States.

It was not a very important food crop at all, but it suddenly became one, all over the place, at the same time. That defies our usual expectations. We like to think of things diffusing out from one place and then the idea spreads out in waves. That does not appear to be what’s going on here.

By Sarah Vickery, College of Letters & Science