Between 7,000 and 9,000 years ago—during the middle Holocene—the Four Corners area went through a slow but dramatic climatic shift. As the region became hotter and drier, stream and lake levels dropped, and larger game animals and firewood became harder to find. Indigenous communities had to rely on foods that were less nutritious and took more time to prepare, such as grass seeds and chenopodium seeds, a tiny grain similar to quinoa.
But recently, archaeologists working with local tribes have recognized a surprising addition to these early food sources: Eleven millennia ago, communities at the North Creek Shelter—a rock overhang in southern Utah’s Escalante Valley—began harvesting a unique species of potato. That’s the earliest known use of a potato in North America, and the evidence suggests that the nutritious tuber helped communities adapt to climate change during the middle Holocene, even as other food sources disappeared.
Now, this potato—and the Westerners who still harvest it—may hold answers to present-day challenges that face the region, including climate change, food security, and reestablishing tribal connections to the land.
* * *
Archaeologist Lisbeth Louderback researches the effects of the middle Holocene climate shift on humans’ diets by sifting through plant remains from ancient hearths. By microscope, she identifies the charred seeds, grains, and other leftovers from meals cooked thousands of years ago to understand how people’s diets reflected their shifting worlds. But one set of samples from fire pits built at North Creek Shelter defied her expertise, resembling nothing she could identify. So Louderback tried something unusual: She analyzed the residues left over millennia on manos and metates, grinding stones and surfaces used to prepare corn and other foods, found at the site. She and her colleagues came to a surprising realization: Almost 11,000 years ago, people in the region were eating a species of potato, known as Solanum jamesii, that’s different from the potatoes widely eaten today, Solanum tuberosum.