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Teeth: Mapping our past mobility

A treasure trove of information for archaeologists, our teeth can reveal our journeys, even centuries later.

Jenny Dare

Ancient teeth can be analysed by archaeologists to uncover patterns of migration. “With some sleuthing, the chemical composition of a person’s tooth provides a mini-life history,” says  Carolyn Freiwald, archaeologist and associate professor of Anthropology at the University of Mississippi, United States, who studies the biology and chemistry of teeth. 

When teeth form, elements from food and water, such as oxygen, nitrogen and carbon, are incorporated into them. These chemical traces reveal where food was grown and consumed. “In cultures around the world, we’ve found people whose teeth tell us they migrated. We often think of ancient people as stationary, but in reality, people have always been mobile,” Freiwald explains.  

Unlike bones, which regenerate through our lives, teeth do not produce new cells when they form. The first molar, for example, forms and sets during infancy, chemically “recording” a baby’s diet. The wisdom tooth contains a diary of what an adult eats, and where their food originates. A mouthful of teeth can provide us with a map of where a person lived, between birth and burial. 

It’s not only teeth that give us clues. The mineralized dental plaque or calculus – tiny layers of food and bacteria which build up where teeth meet gums – contains twenty-five times more DNA than a bone. In 2019, researchers from the University of Adelaide, Australia, used calculus from the teeth of ancient Polynesians to decipher the timings and exact migration routes of prehistoric humans in the Pacific. Anthropologists suggest that researching dental calculus could unearth answers to the riddles of past migratory patterns.

Today, forensic scientists apply these techniques to identify migrants who die during perilous journeys. As Freiwald adds, “It’s a bit harder, since modern people eat food from so many different places, but if our combined work in this area can bring a person home to their family, it’s worth the effort.”

Read more:

Pacific pioneers, The UNESCO Courier, August-September 1991


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