Archaeologists: Potatoes Ubiquitous in Ancient Peru

Published online: Nov 05, 2018 Articles
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Source: Forbes 

We may think of potatoes as the most basic of foods, given their modern ubiquity and low cost, but in the Moche culture in ancient Peru, archaeologists had assumed they were highly charged symbols of the elite because they were found only in artifacts. New research, however, has shown that our understanding of New World potato consumption is biased by the fact the starchy vegetable is nearly always consumed in its entirety.

In a forthcoming article in the Journal of Archaeological Science, researchers Guy Duke of the University of Texas Rio Grande Valley and Victor Vásquez-Sanchez and Teresa Rosales-Tham of Arqueobios in Peru outline their method of starch grain analysis from ceramic and stone artifacts to investigate the use of potatoes in the Moche diet.

Puno, Peru: Portrait of a young woman sitting among potatoes at her stall.

Their archaeological investigation focused on the site of Wasi Huachuma, located in the lower Jequetepeque valley of Peru, dating to 600-850 AD or the later years of the Moche culture. This site featured a platform mound, associated out buildings, burials, and a large residential area. The Moche civilization is well known for massive ritual structures like the pyramidal Huaca del Sol and Huaca de la Luna, as well as for their extensively varied ceramic tradition that includes depictions of sex acts. Some Moche religious practices even involved ritual human sacrifice.

Given the rich history of impressive material culture, less research has been focused over the last century of archaeological investigation of the Moche into domestic contexts, including what food people were eating. But a recent turn in anthropological archaeology away from elite-only contexts to the remains of common people has greatly enriched the prehistory of cultures around the world.

At Wasi Huachuma, a number of artifacts related to food processing were discovered, such as grinding stones, cutters, scrapers, ceramic graters, and the remains of food items themselves. Preserved at the site were a number of animal bones, as well as maize kernels, squash seeds, beans, and chili peppers. These macrobotanical remains were found through sifting or floating of the dirt produced during archaeological excavation. But a macrobotanical approach misses any food item that is completely consumed, like the potato.

Potato plantation in Cusco, Peru

Potatoes were known to be present in the Moche culture, but previously archaeologists only knew them from artifacts such as bottles shaped like potatoes, many with human form. While the potato was first domesticated in southern Peru about 10,000 years ago, the archaeological evidence for potato production is slim to none. Between the lack of potato remains and their depiction in ritual style ceramics, many have assumed that potatoes were largely an elite food among the northern Moche.

To test this assumption, Duke and his colleagues took samples from a grinding stone and from multiple ceramic sherds discovered at Wasi Huachuma to look for microbotanical remains of potatoes. These residue samples were then examined under a microscope, comparing the characteristics of the botanical remains with known reference samples.

Duke and colleagues discovered that all ceramics that they tested contained potato starch, and two of the samples also yielded evidence of maize. What this means for the Moche diet, Duke tells me, is that potatoes "were boiled in a stew on the coast of Peru, although this does not mean they weren't eaten in other ways. Roasting by putting things directly on hot coals or stones was a very common cooking method as well; this would be very hard to document archaeologically, as it would leave no residues on pots and the entire potato would likely have been consumed."

A closeup of a plate of Peruvian ceviche with Spanish onions, corn and sweet potato.

Potatoes figure prominently in contemporary Peruvian cuisine, Duke says, as a side to ceviche, antichucos, papas a la huancaina, and a number of other dishes, and he sees a tradition of this dating back centuries. "The Moche were not just eating maize, beans and squash -- and manioc and chili peppers -- with their seafood and fish," he tells me, "but also potato, and probably a lot of it."

While the yellow potato is the most frequently eaten today in Peru, Duke thinks a number of potato varietals may have been consumed in the past. "There are literally hundreds of varieties of potatoes documented in the Andes, with multiple colors and shapes," he tells me. "But it is very difficult to see these varieties in the archaeological record, especially when dealing solely with starch grains."

The only other example of potato recovered from a Moche context, Duke and his colleagues conclude in their article, were starch grains found in the dental plaque from a burial at another site called Huaca Cao Viejo. But these archaeologists believe that, in general, "the paucity of direct, physical evidence for potato from more Moche contexts is due to the over-reliance on macrobotanical analyses and the under-use of starch grain analysis."

"Ultimately," they conclude, "the identification of potato as part of the common diet at a Late Moche site alters our understanding of Moche culinary tradition. Potato has been understood as a highland food with some presence on the coast, but mostly as a novelty food for irregular consumption by elites." The new evidence that Duke and colleagues have produced from Wasi Huachuma "indicates that potato was consumed regularly and across socioeconomic status lines."

In short, archaeologists can now add potatoes to the list of dietary staples of this ancient Moche society, along with maize and beans. Given the importance of potato as an inexpensive, fiber-dense food for the rise of the later Inca Empire and for the much later growth of 19th century Europe, work done by archaeologists such as Duke, Vásquez-Sanchez, and Rosales-Tham is crucial for our understanding of the development and collapse of civilizations.