What We Work On

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Paleofeces (Coprolites)

The rich record of food, diet, and nutrition packed into paleofeces cannot be equaled in other data bases. First, paleofeces represent the remains of the food, medicines, and other items that passed through the human gut. Most of this would have been ingested intentionally. There is no closer proxy record of human diet (I'll spare you a photo of coprolites here). We find that examining paleofeces for multiple types of remains is extremely valuable when one wants to examine the entire contribution that plants have made. Many plants are represented only in one or two of the following data bases.
Types of analysis we conduct on paleofeces include:

1) pollen
2) phytolith
3) starch
4) macrofloral remains
5) parasite

Pollen

Pollen contained in paleofeces represents pollen originating both in the environment and from foods consumed. I have seen scant pollen records that appeared to represent pollen that accumulated on the surface of drinking water, but not from foods consumed. In that case, the pollen record was accompanied by algae. Some coprolites are dominated by a single or a few pollen types, representing foods collected while they were in flower. Other coprolites exhibit a wide variety of pollen types that might represent pollen residual in the gut from previous meals, since pollen transit times vary considerably. It is possible for pollen to stay in the gut for 30 days, so individual coprolites do not contain pollen or other remains that represent either food consumed in a single meal or a single day. The pollen record is expected to be rich in both prehistoric and historic contexts.

Phytoliths

Phytoliths include both opal silica and calcium oxalates. Paleofeces provides an excellent preservation environment for both types of remains. Although the human gut was not designed to deal with foods with heavy silica content, nevertheless, we have adapted to cereals including Zea mays (maize/corn) in the New World and wheat (Triticum), barley (Hordeum), oats (), rye (Elymus), and rice (Oryza) in the Old World. Each of these cereals has its own phytolith signature.
New World cultigens such as beans (Phaseolus) and squash/pumpkin (Cucurbita) produce unique phytoliths. Opal silica phytoliths produced in the cobs and glumes of maize/corn (Zea mays) are proving to be diagnostic.
Cucurbita phytoliths are produced in the rind. Piperno (date) reports differences in Cucurbita phytoliths that might be used to identify type of squash/pumpkin. We are working to develop a key to cultivated Cucurbita in North America that can be used to identify type of squash/pumpkin from phytoliths recovered from rinds.
Although there is a generic calcium oxalate produced in the leaves and fruit pods of legumes, identification remains at the family level at present. For Phaseolus, cultivated bean, the opal silica hook-shaped hairs produced on the exterior of the Agreen bean" pods appear to be diagnostic. Recovery of these silicified hairs in paleofeces indicates that Agreen beans" were consumed, either fresh or dried and reconstituted.
Zea mays cobs and glumes (those papery things that get stuck in your teeth when you eat corn-on-the-cob) produce phytoliths unique to this portion of the plant. In paleofeces, recovery of these phytoliths indicates consumption of maize. These phytoliths, like all others, represent casts of the inside of plant cells. In the case of maize cobs, the process of genetic manipulation put its stamp on the cells. Therefore, opal phytoliths can be considered a proxy for the genetic signature of maize cobs. It is this fact that makes possible identification of the individual race of maize through computer measurement of phytoliths. Although the size of the phytoliths probably represents environmental conditions, measurements include shape parameters, representing the shape of the cells, which is under genetic control. By measuring a population of 50 phytoliths we produce a mathmatical signature of shape parameters. It is possible that size will prove to be related enough to environmental signature that mathmatical averages will be retrodictive of growing conditions, specifically available moisture. We are currently conducting research in these areas.
Gathered Plants. Numerous gathered plants contain calcium oxalate crystals. Druses are noted in Chenopodium (goosefoot) greens, Atriplex (saltbush etc.) leaves and fruits, spinach (Spinacia B an Old World cultigen), and many other plants in the Chenopodiaceae family. We have found size of the druses to be important in distinguishing between Chenopodium greens and Atriplex fruits, which is important in identifying which food was consumed. Typha (cattail) produces a needle-like raphid that can be recovered from paleofeces, making identification of cattail roots easy. Yucca produces larger (fatter) raphids. In populations where yucca was chewed and quids formed, these raphids are abundant (Cummings 19...). Agave produces even larger and fatter raphids.
Legumes produce a typical calcium oxalate crystal that can be used to identify consumption of members of this family such as mesquite in the Sonoran Desert, and a variety of other legumes in other parts of North America.
Other plants also are represented in the paleofeces phytolith record.

Starch

Although starches should be dissolved in the mouth and gut, some survive to be eliminated in paleofeces. Their identification provides valuable evidence concerning consumption not only of starchy seeds such as maize, but also starchy roots and tubers.

Macrofloral Remains

Macrofloral remains are, perhaps, the best known remains recovered from paleofeces. They are often visible to the naked eye of the excavator. Both prehistoric and historic North American diets were rich in seeds and other items that are part of the macrofloral record. Often grinding even small seeds such as Cheno-am seeds leaves debris large enough to be identified as part of the macrofloral record. Remains of many gathered foods such as grass seeds, mustard family seeds, prickly pear cactus, mint famly seeds, legumes, groundcherry, portulaca, saltbush, and sunflower seeds have been observed in paleofeces. In the Sonoran Desert, consumption of mesquite sometimes includes the mesocarp, which are identifiable.

Parasites

Both Ascaris and Trichuris (roundworm) (whipworm) eggs are produced in abundance and are easy to identify when present in paleofeces. Enterobius (pinworm) eggs are not as abundant in paleofeces, and are known to occur in less than 5% of infected populations. Parasites that live in fish flesh, such as Diphyllobothrium (Dibothrycephalus), a tapeworm that infect humans when we eat raw or undercooked fish containing the parasite. These parasites live in fish in temperate regions. When we recovered then in paleofeces deposited in the Atacama Desert of Chile, our interpretation was that the people who passed through this area had been in the Altiplano eating fish from the lakes. The site that yielded the paleofeces was on a caravan route from the Altiplano to the coast or vice versa (Cummings, Nepstad-Thornberry, and Puseman 2000).

References

Cummings, Linda Scott and Kathryn Puseman
2002 Pollen, Phytolith, Starch, and Macrofloral Analysis of Paleofeces from Connley Cave 5 (Site 35LK50), Fort Rock Basin, Oregon. Ms. on file with Paleo Research Institute and State Museum of Anthropology, University of Oregon, Eugene.
Cummings, Linda Scott and Kathryn Puseman
1992 Pollen, Phytolith, Parasite, and Macrofloral Analysis of Coprolites from Room 21 in Step House (5MV1285), Mesa Verde National Park, Colorado. Ms. On file with Paleo Research Institute and National Park Service, Mesa Verde National Park.
Cummings, Linda Scott
1994 Anasazi Diet: Variety in the Hoy House and Lion House Coprolite Record and Nutritional Analysis. Chapter 9 in Paleonutrition, The Diet and Health of Prehistoric Americans, edited by Kristin D. Sobolik, Occasional Paper No. 22, Center for Archaeological Investigations, Southern Illinois University at Carbondale. pp. 134-150.
Cummings, Linda Scott, Curtis Nepstad-Thornberry, and Kathryn Puseman
2000 Paleofeces from the Ramaditas Site in Northern Chile: Addressing Middle to Late formative Period Diet and Health. Ms. On file with Paleo Research Institute and Beloit College, Beloit, Wisconsin.
Scott, Linda J.
1979 Dietary Inferences from Hoy House Coprolites: a Palynological Interpretation. The Kiva, 44(2-3):257-281.