The remains of two pits used as latrines in Guatemala shed light on the eating habits and culinary culture of the Mayans.
Ancient toilets and dumps are a treasure trove for archaeologists. While they may not be home to gleaming medieval jewels or the splendor of intricate Roman mosaics, they are brimming with countless “relics” from past civilizations. The waste of our ancestors sheds light on the lives of ordinary people who did not live in palaces or have chests of gold. In these ordinary and dirty places, archaeologists can find out what people used to eat and drink, how they cleaned themselves, what diseases they suffered from or what they kept.
Archaeologists studying two circular pits dug more than a thousand years ago in the corner of a house in central Guatemala have uncovered new insights into the lives of the Maya people. Archaeologists have uncovered how the Maya made tamales (a traditional Mexican dish) from corn and what they poured into indoor toilets. They also found parasites in the pits that caused nausea, malaise and diarrhea.
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In a study accepted for publication in the Journal of Archaeological Science, researchers from Boston University, Harvard University and the University of Texas found that the pits were filled with corn starch crystals. These microscopic crystals were produced by soaking corn cobs in a mixture of alkaline water and lime, a process used to make Mexican foods such as tamales and tortillas. Since parasite eggs found in human feces were also found in these pits, the archaeologists concluded that the Mayans used these pits as toilets and also poured the leftovers of the solution they used to make tamales into these toilets.
“We have the earliest evidence of alkaline cooking (i.e. nikstamalization) and toilets in the Maya world,” said John M. Marston of Boston University’s School of Arts and Sciences.
Pursuing at least some of this evidence since 2020, Marston and then-student Emily S. Johnson developed a method for detecting the remains of nickstamalization in pots, archaeological deposits and grinding stones. According to the University of Gastronomic Sciences in Italy, nickstamalization is “the secret of pre-Spanish invasion culinary culture.”
The Brink interviewed Marston, who directs Boston University’s archaeology program, about historic toilets, what we can learn about ancient eating habits from tamales, and what was found in pits in Guatemala.
Your research focuses on the chemical processes used by the ancient Mayans to enhance the nutritional value of maize, which you refer to in your article as “a process that radically changed Mesoamerican eating habits”. What is the history of this process? How does it work and why is it so important?
Marston: We find it in societies where agricultural systems developed around maize. So you can see it being used in North America as well as Central America. The way people prepare and use maize varies from region to region, but the chemical method is the same. This method basically consists of soaking the corn in an alkaline solution, which increases the nutritional value of the corn and makes it easier to knead the dough.
In North America, we can see this tradition in coarse cornmeal, which can be eaten in soup or used to make cornbread. In the American South, this flour is still used today. In Central America, it is more common to grind the cobs and make dough – tortillas and tamales are also made from this dough. This method makes the dough easier to knead, especially in tortillas. The fact that such a gluten-free bread can be made from this material is a remarkable development. Evidence from the earliest historical and pictorial records from the period of contact with the Spaniards shows that many communities in Central America used this method to make tamales and tortillas, and that it was one of the foundations of their culinary traditions.
How can we recognize that an ancient piece of corn has undergone this process?
That was the question that remained unanswered. There was no record of the use of tamales and tortillas outside of historical or pictorial records of early Spanish interaction, but we knew that this method was in use at the time. If you look at the early iconographic records, there are some examples of tamales being used in the Maya world even before Spanish interaction.
The main problem was that there was no method to detect the remains from this process, which made it difficult to study earlier periods to see how widespread it was. For example, depictions in the Mayan world only appear in palaces or places like that, so we don’t know how much these depictions were part of everyday life. What we do find is that the chemical process changes the molecules of the crystal, and therefore the paste.
What do you know about the pits where you found the samples?
These places are called “chultune”, which means pit (or rock pit). They are among the characteristic structures of the Mayan world. The area now known as the Yucatan Peninsula has an extremely soft limestone bedrock, and this easily scratched rock has been scratched by humans for a variety of reasons. We speculate that many of these pits were cisterns to store rainwater for use during dry periods.
However, we cannot say that this was the case everywhere in the Maya world. It is clear that these pits served a complex set of purposes. We have examples of ritual use of these pits to communicate with the underworld, which is important in Maya cosmology. In other cases, they were used for more mundane needs, for example as storage or as garbage dumps. In these examples in Guatemala, when we were looking at the microscopic remains, we found tapeworm eggs, which we assume came from human feces, suggesting that these pits were used as latrines. Thus, we have evidence to support a suggestion that has been made in the past, but no one has been able to provide direct evidence.
So were the grains you found something that people had eaten and defecated? Or were they by-products of the milling process?
We don’t know whether these crystalline particles were well preserved after passing through the human digestive system. But we do know that if you take the alkali – the Maya used lime – make a mixture of nickstamal, then add dry corn cobs to this mixture and heat it, you get this liquid. Moreover, the cobs had to be washed before use to remove this highly alkaline and caustic liquid. Given that this liquid is a bit of a toxic waste, how can we get rid of such a liquid? Well, the latest evidence suggests that it was poured down the toilets. And the reason we think this is because in many parts of the world today, pit latrines outside houses are lined with lime to repel bad odors and insects, thus preventing biological activity. So pouring this waste solution into the toilet was a convenient way to get rid of the solution and to reduce the odor of the toilet inside the house.
What can you say about the people living where these pits are? Where did they live? When did they live? Who were they?
This place, known as San Bartolo, was inhabited in several different historical periods. But the period that the chultunas we excavated date from is the Classic period. The reason why this period of the Maya is called the Classic period is because this is when they built their largest cities and monuments. Probably in the eighth or ninth centuries AD, this was the period when the city was at its largest. The Maya had a very deep-rooted and rich culture, and the Classic period was just one of the periods when they built cities. Today we often think of the Mayans as an ancient people who built huge cities and then disappeared, but the Mayans existed long before we think of them, and they still do.
Is being an archaeologist always so glamorous? Do you often dig in toilets and garbage dumps to discover traces of the past?
Actually, toilets are one of the archaeologists’ favorite things to find. No matter where in the world you work, no matter what period you are studying, toilets are worth their weight in gold, because you can learn unique things from them. You can find remains that have come out of people themselves and show what people ate; for example, in this particular study, we found tapeworm eggs that came out of human stomachs. One of the things that often happens is that people drop things in the toilets and don’t bother to go down and get them, so you can also find some valuable objects that people have lost; of course, you can also find garbage, because people would occasionally throw their garbage in the toilets. Archaeologists working in historic New England spent all their time in the toilets. I worked in a couple of Roman toilets during my research in Israel and Turkey. Again, you can find great things there.
Boston University / Santini, L. M., Weber, S. L., Marston, J. M., & Runggaldier, A. (2022). First archaeological identification of nixtamalized maize, from two pit latrines at the ancient Maya site of San Bartolo, Guatemala. Journal of Archaeological Science, 143, 105581.
