For most people, tooth plaque is an annoyance, but for researchers it can be a valuable tool in unlocking the mysteries of little-understood cultures.

For most people, tooth plaque is an annoyance, but for researchers it can be a valuable tool in unlocking the mysteries of little-understood cultures.

Such is the case of two scientists who studied the dental remains of people living on Easter Island prior to European colonization.

While the early inhabitants are famous for having built the large heads that have become synonymous with the landmass, little else is known about them, including what they ate to survive.

The researchers believe they’ve cracked the case, but the path to discovery did have a few unexpected curves.

Early testing suggested that the foodstuff locked in the hardened dental matter was palm.

Given the proximity of the dates of settlement and the extinction of palm from the island it was a largely inexplicable find.

A deeper analysis of the starch grains studied revealed that they were strikingly similar to those found in sweet potatoes.

So, they tested out some modern tubers grown in sediment with properties similar to those found on the island.

Their hunch was correct, and it turned out that palm microfossils still existing in the soil were absorbed by the sweet potatoes, which they believe was a more likely early food source.