If you've ever eaten a sandy batch of shellfish, you know the feeling: the terrible crunching and grinding that cracks through your jaw, making you question the wisdom of your choice of food. Now imagine that feeling with every bite you take, every meal of every day.
If a new study is right, that's what early humans and animals felt after the Laacher See supervolcano exploded in central Europe 13,000 years ago, and it drove them out of the region.
Laacher See was a tremendous blast. It devastated 540 square miles of forested land right around the crater and conservative estimates suggest an area the size of Minnesota was covered in a blanket of ash and rock bits.
Flung into the air at the slightest breeze, the fluffy mixture of tephra particles stung the eyes, irritated the lungs and coated anything animals or people would have cared to eat. For game animals like elk, hare and reindeer, chewing plants would've ground their teeth to the pulp and left them starving.
Wildlife probably fled the worst affected areas of central Europe, leaving northern tribes living in Germany, the Netherlands and southern Sweden marooned on a withered landscape. Populations dwindled, and archaeological evidence suggests they abandoned bows and arrows in favor of more primitive hunting spears.
"We have very little information on how small scale hunter-gatherer societies would respond to this," said Felix Riede of Aarhus University in Denmark. "Would they just leave? Or would they try and deal with the tephra?"
In a study published in the Journal of Archaeological Science, Riede and colleague Jeffrey Wheeler of the University of Cambridge in the United Kingdom show that the volcanic particles are about twice as hard as most mammal teeth, including those belonging to humans.
Any meal seasoned with a coating of tephra would have been miserable, if not life-threatening.
Even a few months of exposure to tephra could have been devastating. But Riede and Wheeler think it could have lingered on the landscape for as much as 300 years, carried away by rain only to return in drifting, wind-blown dunes.
Still, John Grattan of Abersystwyth University in the United Kingdom points out that there is a silver lining to the Laacher See eruption.
"The people living in Central Europe adapted to these intense stresses," he said. "They were able to cope with them, and to survive."
"We grew up in a volcanic environment," he added, noting that most of our fossil records of early humans come from the volcanically active region of eastern Africa. "That kind of pressure and stress, if it doesn't kill you, it makes you stronger, as our friend Nietzsche would say."