The warm, moist environment of your mouth makes it a great place for bacteria—some of which keep busy causing cavities. Such dental difficulties were thought to have really taken off when we switched from hunting-gathering to agriculture and had a ready supply of farmed, fermentable carbohydrates.
Now research shows that at least some pre-agricultural humans also had a bad case of tooth decay. The study is in the Proceedings of the National Academy of Sciences. [Louise T. Humphrey et al., Earliest evidence for caries and exploitation of starchy plant foods in Pleistocene hunter–gatherers from Morocco]
One hunter–gatherer site in Morocco called Grotte de Pigeons was a key ritual and economic center. The deposits there date to some 15 thousand years ago and are incredibly dry. So organic material, including bones and charred plant remains, is well-preserved.
Researchers found leftover pine nuts, juniper, pistachio, wild oats, and—particularly popular—carbohydrate-rich acorns. Eaten raw or as flour, acorns can stick in teeth. The foodstuff makes a happy home for acid-loving bacteria that cause cavities.
The scientists also analyzed teeth from 52 partial or complete jaws. They found that more than half the teeth showed signs of lesions. And only three of the adults were cavity-free. Thousands of years before folks in the area learned how to farm.
[The above text is a transcript of this podcast.]