Tooth Decay Among the Mummies

In the summer of 2009, Dr. James Watson, assistant curator of bioarchaeology at Arizona State Museum and assistant professor in the UA’s School of Anthropology, travelled to Chile on a Fulbright grant to conduct research and teach at the University of Tarapaca at Arica.

Dr. Watson, with colleagues Bernardo Arriaza and Iván Muñoz Ovalle, set out to explore the oral health of the prehistoric Chinchorro people and their descendants by conducting dental exams on mummies and skeletons.

The Atacama Desert of northern Chile and southern Peru is the driest desert in the world and yet it was able to support one of the earliest known permanent cultures. The Chinchorro, the earliest known practitioners of mummification, were expert fishers who settled along the Andean Coast circa 8000 BCE, 6000 years before farming became common practice there. Once plants and animals such as corn, potatoes, and llamas were domesticated in what is called the Formative Period (1500 BCE–500 CE), people began to settle further into the valleys where farmland was available.

The team postulated that coastal groups would consume more foraged marine foods than the valley groups who would rely more on domesticated foods.

“If this shift opened the door to significant changes in diet and lifestyle, health patterns would also be affected and this shift would surely show in the teeth,” said Watson. “We would expect that the farmers, consuming more processed carbohydrates such as corn and potatoes, would show more tooth decay.”

In order to determine if patterns in oral health were different between the coastal fishers and the valley farmers the team recorded tooth decay and tooth loss in 200 Formative Period skeletons and mummified individuals from the lower Azapa Valley (along the northern Chilean coast).

The team found that, although the valley dwellers had four times the cavities, tooth loss was similar when compared to the coastal residents. While tooth loss was likely due to tooth decay among the valley groups, it was common on the coast as a result of tooth damage from the hard marine diet. This pattern was maintained for the 2,000-year duration of the Formative Period, indicating that once the diet changed it remained relatively stable for a long time.

“We see clear links between coastal and valley groups, with little distinction, throughout the Formative Period,” said Watson. “Most importantly, we see that the introduction of agriculture only created new dimensions and new resources available to the long-time fishers rather than supplanting fishing altogether.”

While the adoption of agriculture caused profound changes in lifestyle and health patterns throughout South America (indeed throughout the world), there doesn’t seem to be much change in this small corner of the Atacama Desert. Rather, there appears to be an entrenchment of traditional resource exploitation.

“This is an example of how human decision-making affects the course of evolution,” concluded Watson. “Bottom line - the more things change, the more some people want them to stay the same.”

The full report on this research will be published in the December 2010 issue of Latin American Antiquity. (Link opens in a new window.)