Ed Yong in The Atlantic:
Neanderthal dental plaque is a precious commodity, so it’s a little embarrassing when you’re trying to dislodge a piece and it goes flying across the room. “We just stood still, and everyone’s like: Where is it? Where is it?” recalls Laura Weyrich from the University of Adelaide. “Usually, we try to wrap the skull in foil and work underneath it, but that time, the foil didn’t happen to cover a small area.”
Weyrich and her team of unorthodox dentists eventually found the wayward plaque, and recovered similar samples from the skulls of five Neanderthals. Each was once a colony of microbes, growing on a tooth. But over tens of thousands of years, they had hardened into small, brittle pieces of rock. Still, each nugget contained DNA—from the microbes, and also from whatever the Neanderthals had eaten.
By harvesting and sequencing that DNA, Weyrich has shown that there was no such thing as a typical Neanderthal diet. One individual from Spy cave in Belgium mostly ate meat like woolly rhinoceros and wild sheep, as well as some edible mushrooms. But two individuals who lived in El Sidrón cave in Spain seemed to be entirely vegetarian. The team couldn’t find any traces of meat in their diet, which consisted of mushrooms, pine nuts, tree bark, and moss. The Belgian Neanderthals hunted; the Spanish ones foraged.