NATURE NOTES:
Pecos River Pescatarian? In a Buried Bowl, Archeologists Find Traces of the Prehistoric Desert Diet

Microscopic plant remains – such as the “phytoliths” and starch grains pictured above – give archeologists insight into the human use of plants hundreds, and even thousands, of years ago.

Finding a “potsherd” – a fragment of prehistoric pottery – is arresting, a potent reminder of the Native American past. It’s always best to leave such objects in place – both so others can have the experience, and because, for archeologists, the context of an artifact can yield as much insight as the object itself. But as fascinating as such a find is, in parts of our region it’s not uncommon. 

Finding a complete pot is another matter. In 2009, in desert country east of Carlsbad, New Mexico, archeologists found such a complete vessel, about 8 inches wide and 4 inches deep, of a style called Jornada Brown. The researchers, and the mining company funding their work, recognized a rare opportunity, and they assembled a band of archeologists – each with specific expertise – to unlock the pot’s secrets.

The results were published in 2018, as “What’s for Supper?,” a chapter in “Late Prehistoric Hunter-Gatherers and Farmers of the Jornada Mogollon,” from the University Press of Colorado. It’s a unique glimpse into the diet and lives of the people who lived in what’s now eastern New Mexico and West Texas. And it reminds us how mysterious those lives remain. 

On a hill 20 miles east of Carlsbad and the Pecos River, the Rascal Rabbit site offers a sweeping view east toward the Maroon Cliffs, and the Llano Estacado beyond. With springs nearby, it attracted prehistoric people for thousands of years. 

The site is also located near the Intrepid Potash Mine, and in 2009 the mining company was acquiring the land in a swap with the Bureau of Land Management. Federal law required an archeological survey first. 

Douglas Boggess, of Lone Mountain Archeological Services, had two “grandmothers” on his crew – one from the Navajo Nation, the other from Georgia – and he tasked the two women with scraping away a layer of sand at the site.

“And sure enough, as they began to scrape, they exposed about half of the rim of the vessel,” Boggess said. “Oh – that is a pot! It was very much a surprise. I think it was the first one that has been found for several years in that area. This one was complete, no kill hole, and had obviously been left in place, in a hearth, in situ, because someone intended to return to use it again someday.”

Such prehistoric pots likely once existed across West Texas and New Mexico, cached by ancient people for later use. Most were lost due to livestock grazing and other modern impacts. The Rascal Rabbit vessel was only a few yards from a road, and Boggess said it was “miraculous” it had escaped destruction.

The pot was held in place by soil, and though complete, was broken into 49 pieces. Cooking residue lined its interior. 

There was traditional analysis to be done. Radiocarbon dating showed that the vessel had been placed above a fire – fueled with javelina bush – between 1185 and 1280 CE. “Petrographic” analysis revealed  the pot was tempered with volcanic rock from New Mexico’s Sierra Blanca Mountains. The vessel had been made in a farming village in those highlands, 120 miles away.  

But the mining company committed funds to go further. Analysis of the cooking residue, and of the material above and beneath the pot, could show more.

Chad Yost, who worked for PaleoResearch Institute in 2009, brought his specialty to the project – analysis of microscopic plant remains, including those known as “phytoliths.” 

“It’s kind of a mind-boggling array of possibilities,” Yost said, “when it comes to linking phytoliths you find in the soil or in archeological contexts back to some plant growing on the landscape or that had been utilized by someone.” 

In Greek, “phyto” means plant, and “lithos” means stone. Some plants deposit silica in parts of their tissues, and these tiny, stone-like particles can endure for millions of years. Phytoliths have been recovered from fossilized dinosaur dung. 

In the Rascal Rabbit pot, Yost found starch grains from grass seeds. Globally, grass seeds were a mainstay of the hunter-gatherer diet. They were ground into flour, and could be eaten as a gruel – a prehistoric cream of wheat.

But Yost also found something surprising – within and below the pot, and in the residue, he found abundant phytoliths of a plant called Commelina erecta, or whitemouth dayflower. 

Its presence in the residue suggested it had been cooked intentionally. But the plant is not known to have been a food source in the Americas. Combing the academic literature, Yost learned that hunter-gatherers in East Africa cooked Commelina as an edible green. Some reports suggested hunter-gatherers used the plant medicinally.

Traditional foragers had detailed knowledge of wild plants, most of which has been lost. Ancient people here may have used the dayflower for purposes we can no longer determine.

Mary Malainey is a professor at Brandon University in Canada. Two decades ago, she pioneered a new form of a technique called “lipid analysis.”

“Essentially, I’m an archeologist,” Malainey said, “and my lab looks like an organic chemistry lab. So it’s kind of different.”

Lipids are fats and oils found in both plants and animals. The most familiar animal lipid is cholesterol. Remarkably, lipids can endure in cooking vessels, or in rocks used in cooking, for thousands of years. 

Malainey has taken plant and animal samples from across the plains – from Texas to Manitoba – cooked them, and heated them for months, to replicate the process of decomposition. It’s allowed her to ID lipids from prehistoric artifacts. 

From a single piece of the Rascal Rabbit vessel, she extracted lipids from the interior, and used a technique called gas chromatography to separate them.

She found that the bowl had been used to prepare plant food – perhaps mesquite, or corn. She also identified lipids from a fish or bird. Other clues suggested that, indeed, fish was on the menu. A stone tool at Rascal Rabbit contained proteins from a gizzard shad – a fish native to the Pecos River.

Linda Cummings of PaleoResearch Institute used a technique called infrared spectroscopy to confirm Malainey’s findings, and also showed that the pot had held baked agave.

In the years since, Cummings has analyzed hearths from 500 Permian Basin sites. Commelina, it turns out, is common. 

“I’m still so puzzled by this issue of where do we have these things and why do we have them in the features that we do,” Cummings said. “Well, then I started looking at ground-dwelling birds.”

The presence of Commelina is closely correlated with quail habitat here. Quail eat stones and other hard objects to aid their digestion, and commelina seeds fit the bill. Cummings thinks the ubiquity of commelina in hearths may reflect the quails’ use of the abandoned hearths for roosting. And for prehistoric hunters, of course, the quail would have been a boon.

The Rascal Rabbit pot analysis was cutting-edge. But many questions remain. 

Were those who cached the pot the same people who made it? Did they farm the highlands in summer, and travel to the plains east of the Pecos in winter? Or were the pot’s users desert people, who’d traded for it with upland villagers?

The Rascal Rabbit pot can’t answer those questions. But it does shed light on the complex, resourceful lives of our region’s prehistoric people.