Pica, Geophagy, and Rock Art: Ingestion of rock powder and clay by humans and its implications for the production of some rock art on a global basis.

(C) 2000 Kevin L. Callahan, A Paper read at the Philadelphia SAA Conference on April 8, 2000

Pica ("PIE-KA") is the desire to ingest non-food substances such as rock powder, clay, chalk, dirt, and other material, by some humans, most commonly pregnant women, young, and patients with chronic kidney disease.. It is a common phenomenon also seen in many animals. Geophagy ("GEE-OFF-A-GEE") has been defined as "a practice in rural or preindustrial societies of eating earthy substances ([such] as clay) to augment a scanty or mineral-deficient diet" (Merriam-Webster 1999:488).

"In Jamaica, in 1992, in a study on the dietary habits of rural women during pregnancy, it was noted that 15 of the 38 pregnant women questioned reported cravings" (Walker 1999). The most common craving in the study (20%), was not for crunchy pickles and ice cream, but was a craving to ingest stone. "The main reasons given for craving a food item were 'I feel like eating it' and 'I get to like it'.. . ." (Walker 1999).

This well documented medical and cultural phenomenon has a direct connection, according to ethnohistoric sources, to the production of some rock art on a global basis, in particular the production of some cupmarks or cupules, occasionally referred to in archaeological literature as "pits."

Cupmarks are hemispherical carvings, typically about 2 inches wide and 5/8 inch deep made in rock by pounding the same spot for between 5 and 15 minutes with a stone hammer producing about a tablespoon of powder or 1 dose. Experiments show it is much easier to make a cupmark on a heavy solid rock or wall rather than something the size of a light field stone.

Globally, cupmarks appear on nearly every continent and have a time depth that extends from the present at least as far back as the Upper Paleolithic (Parkman 1995).

During the late nineteenth century Charles Rau (1881) reported that across Germany and in Sweden "cup-marks" and "grooves" or "furrows" had been inexplicably carved into the outside brick walls and sometimes the mortar of many churches, usually on the south side, near entrances. The reason for the association between European "ecclesiastical structures" and these cupmarks was a mystery to Rau . Rau seems to have viewed it as the continuation of a pagan custom, which it may very well have been, however, knowledge of the medical phenomena of pica and geophagia in humans might have added support to another perspective about this unusual and compulsive appearing behavior on the sides of religious buildings across Germany and Sweden.

Charles Rau recorded that, "The cups on churches in Germany seem to to have been thought to possess healing qualities. Fever-sick people blew, as it were, the disease into the cavities. According to other accounts, the patients swallowed the powder produced in grinding out the cups" (Rau 1881:88).

Rau also described two stones in France attached to or actually inside churches where people ground holes in the stones and drank the powder to cure fever and impotency. He also identified a location in Switzerland where "ailing persons drill into the stones of a certain chapel, and swallow the dust thus obtained" (Rau 1881: 88-89) He then mentioned a citizen of Greifswald who reported "that the cups were still resorted to in his time for charming away the fever" (Rau 1881:89).

In at least one African study similar behaviors were observed. The walls of houses were actually the first place non food items were sought by those practicing pica.

Jannie Loubser has told to me that in Namibia he has seen multiple rows of cupules on the sides of painted shelters and apparently cupules can be found on the sides of the Easter Island Heads and, if the photos can be trusted, the Sphinx of Giza. I know that cupmarks have also been reported to have been carved on the top of Olmec Heads as well.

Animal studies by Mitchell et al. in 1976 on the etiology of geophagia ("Gee-Off-Ah-Gee-Ah") concluded that the phenomenon "may be a response to mitigate the effects of toxic agents that have been introduced into the body" (Simon 1998:654). In similar studies in 1977 Burchfield et al. "reported studies on rats that indicated geophagia increased when rats were made acutely ill. They concluded that geophagia 'may occur in response to any . . . (stress state)'. In particular, the authors noted that geophagia occurred in response to induction of arthritus and as a response to acute gastrointestinal illness" (Id.).

Ethnohistoric information in North America directly associates some cupmarked rock art with couples seeking to enhance fertility (Parkman 1995:8-9). Some production of cupmarks has also been reported to have occurred near the time of births (Id.).

Breck Parkman, for example, working in California, has reported that in Pomo society the powder resulting from cupmark production was sought after by couples wishing to have a baby that otherwise were facing sterility and childlessness (Heizer 1953; Merriam 1955; Parkman 1995:8).

In Pomo and Shasta ethnographic accounts, cupmarks are sometimes equated with fertility and are referred to as "baby rocks" (Id.). According to Merriam the powder from cupmark production was ingested by women in the belief that it made them more fertile (Merriam 1955). The production process for cupmarks was thought to release the underworld's spiritual power that resided in the rock. The action of making the cupmarks was also believed to be able to bring benefits such as game and rain (Loubser,in press; Merriam 1955). The Pomo of Northern California also used dirt in their diet. They mixed it with ground acorn and this neutralized the acid (Rosenberg 2000).

In Sweden, women wishing to become mothers deposited small gifts at cupmarked stones.

In Sweden, cupmarked stones are called elfstenar and unlike children's stories you might be familiar with, in Sweden the elfs are described as "the souls of the dead" who "frequently dwell in or below stones" (Rau 1881:86). "If their quiet is disturbed, or their dwelling-place desecrated, or if due respect is not paid to them, they will revenge themselves by afflicting the perpetrators with diseases or other misfortunes. For this reason people take care to secure the favor of the 'little ones' by sacrifices, or to pacify them when offended" (Id.).

In many animistic religions, underground spirits are associated with curing sickness and fertility so there are pervasive religious aspects as well as practical uses for the rock powder medicines found in nature. Native American shamen were knowledgeable about the health benefits of minerals as well as plants. For example, Ojibwe shamen undertook vision quests to determine from the underground spirits which, of 40 minerals of the earth, should be used to treat their patients (Rajnovich 1989?).

In my own research in the Upper Midwest region of the United States I have noticed that cupmarked boulders such as at Fort Ransom, North Dakota and Blood Run, Iowa are rather predictably composed of granite next to a large chunk of quartz and are typically situated near natural springs and below hills with burial mounds.

The ethnohistoric accounts of the Dakota clearly indicate that to the Dakota boulders were not considered inanimate objects but were the occasional dwelling place of spirits such as Inyan and Taku Skan Skan.

Fine white clay or kaolin comes from the weathering of granite. The fine white clay powder (like talcum powder) that resulted from making a cupmark on weathered granite boulders was probably both a medicine and a symbolic item with protective supernatural "power" (Rajnovich 1994, Callahan 1999).

Kaolin and pectin are still the active ingredients in Kaopectate which is sold in modern drugstores for the treatment of intestinal problems.

White clay in rivers was associated with the underwater spirit associated with mammoth bones in some Upper Midwestern cultures and according to Mary Eastman (1849), the Dakota words "Mine Soto" or "whitish water" was a reference to the white clay in the Minnesota River from which the state took its name. Jack Steinbring has told me that the northern Ojibwe ground up imported conch shells and drank the powder in a tea considering this a spiritual event (Jack Steinbring, personal communication).

Some of you might have seen this month's issue of National Geographic, which in an article on medicines in nature, has a full page photograph of a woman from Georgia chewing white clay for morning sickness.

The caption indicates that the woman "swears by the old-time remedy of eating kaolin, or white clay . . . some women crave it, especially during pregnancy" (Swerdlow 2000:98).

There are extensive anthropological observations of geophagia in Indonesia, Oceania, Africa, and among African-Americans of North America and, like cupmarks, geophagia has been observed on nearly every continent (Anell and Lagercrantz 1958, cited in Simon 1998).

Sometimes non food consumption was undertaken for religious and magical purposes and frequently by pregnant and lactating women (Laufner 1930, cited in Simon 1998).

"During pregnancy, the body requires 20% more nutrients and 50% more during lactation" (Rosenberg 2000). Although especially common in pregnant women geophagia "also occurs in both sexes and at all ages up to 80 y[ears]" (Simon 1998:654).

Geophagia can be a famine food or a regular part of some diets. Native Americans of the U.S. Southwest - eat clay with bitter raw potatoes and Native Americans in southern California - bake bread with clay and corn (Id.). Potatoes are thought to have been initially poisonous and humans learned to eat potatoes with clay. Like other animals, humans appear to instinctively know to ingest clay and rock powder for stomach problems.

The enteric nervous system in the human gut, with 100 million neurons, is described by doctors as akin to a second human brain that learns, remembers, and produces feelings and has a long evolutionary history (Blakeslee 1999).

Mitchell "concluded from rat studies that pica [and geophagia GEE-OFF-A-GEE-A] is an 'illness-response' behavior and is analogous to vomiting in other species" (Mitchell et al. 1976).

The potato that first poisoned some hungry South American was probably instinctively followed shortly thereafter by a dose of clay.

In historic times, Zapotec Indians in Oaxaca, Mexico manufactured tablets of clay for medicinal purposes, formed in shapes of religious images (Green and Jones 1968, cited in Simon 1998).

According to Boyle and Mackey,

"Pica ingestion has occurred for centuries. Ingestion of clay lozenges to treat illness and poisoning was documented as early as 40 B.C.E. in Greece, . . .

The underlying cause of pica is not known; however, pica is associated with a higher incidence of malnutrition.

Several theories have been advanced to explain the reasons for pica, including the body's need to acquire certain missing nutrients, hunger, cultural tradition, prevention of nausea, and attention seeking. There is also a strong link between pica and iron deficiency; however, the exact relationship is not clear.

Pica is thought by some researchers to cause anemia [and] . . other researchers believe that depleted iron stores lead to pica--that pica is a consequence, not a cause of iron deficiency.. . .

Women have related that if they are unable to ingest their nonfood substance, they become worried, upset, and/or anxious . . .

[S]ubjects recounted a variety of reasons for ingesting nonfood substances, such as "craving," "It tastes good," and "It's dry and crunchy." They "wanted it," "liked it," and "It smelled good," . . . (Boyle and Mackey 1999 65-67).

According to an article by Dr. A.R.P. Walker,

"Early descriptions of the habit were given in Aristotle and Hippocrates.. . .

The Roman physician Soranus described how pica was used for the alleviation of subsequent symptoms and the unpredictable appetite in pregnancy, which can include a strong desire for extraordinary foods. He noted that the need began about the fortieth day of pregnancy and persisted for some four months or more.. . .

In the 18th century, when it was learned that the Sultan of Turkey ate a special clay from the island of Lemnos, the Europeans quickly adopted the product as health food . . .

The practice of pica is widespread throughout the world.

Geophagia is particularly common in tropical areas.. . . Contributing factors include hunger, poverty, starvation and famine . . .

Pica may function as a bulking agent to supplement a poor diet . . . In southern Germany, quarrymen partook of 'stone butter' derived from clay, with their food . . .

While the eating of clay is strongly connected to folk medicine and social custom, it also has the quality of compulsive behaviour . . .

In Australia some Aboriginals eat white clay . . . similar to the clay used in kaolin preparations. Clay is . . . eaten to 'line the stomach' before eating yams, or fish that may be poisonous, to allay hunger and to treat hookworm infestation . . .

In the southern states of the US pregnant women . . . believed that such substances helped to prevent vomiting, helped babies to thrive, cured swollen legs and ensured beautiful children. Birthmarks are thought to be the result of an unsatisfied craving…

The practice of pica is widespread in Africa and is variously associated with spiritual ceremonial behaviors.

In Malawi it is reported to be surprising for a pregnant woman not to practice pica 'since this is how a woman knows that she is pregnant'. The taste of clay is claimed to diminish the nausea, discomfort and vomiting in 'morning sickness'.. . .

In rural areas [in some African countries] an estimated prevalence level [for pregnant women who eat clay] is 90%.. . .

There are few women who never take clay. One woman in rural Zimbabwe, 23 years old, married, did not take clay--from the fact that she had never conceived she regarded herself as barren.. ..

Although nutritionists and other observers have tended to view geophagy, and pica in general, as a compulsive craving and as a medicine to alleviate discomfort in some respects . . . Clays could absorb dietary toxins and bacterial toxins associated with gastrointestinal disturbance associated with pregnancy. Geophagy could play a useful role in its proper context and could be appreciated as a normal human behaviour . . ."(Walker, et al. 1997:280-4).

"The clay commonly ingested in Africa contains important nutrients such as: phosphorus, potassium, magnesium, copper, zinc, manganese, and iron" (Rosenberg 2000).

"For females, . . . white clay, at an upper consumption rate of 100g per day, would supply 322% of Recommended Dietary Allowances (RDA) for iron, 70% copper and 43% of manganese" (Walker, et al. 1997:280-4).

In Conclusion. Ethnohistoric sources clearly point to a connection between pica and the production of some cupmarks, but our knowledge and understanding of the extent of this phenomenon is far from complete and there are other related reasons for making cupmarks, such as death stones, where fertility may be sought for rebirth of a recently deceased soul.

It is my hope that by increasing awareness, and triangulating both the cultural and biological reasons for the ingestion of rock powder by humans, that rock art researchers will have another tool to add our discipline's explanatory toolkit.

E-mail: call0031@tc.umn.edu