Charred food residues scraped from the world's oldest pots show humans used ceramics for cooking in the late Ice Age, long before hunter-gatherers settled down to become farmers, a study said Wednesday
The find raises questions about the turning point in history that saw hunters abandon their roaming lifestyle about 10,000 years ago to start domesticating animals and plants and gain food security.
Scrapings taken from more than 100 shards of Japanese pots dated between 11,800 and 15,000 years ago were analysed by mass spectrometry and gas chromatography to derive a chemical "fingerprint" from heating tiny samples.
They revealed fatty molecules called lipids, which came from cooked fish and from "non-ruminant" animals, said the paper published in Nature, adding that further details about the meal were unknown. Non-ruminants include species such as pigs, horses and rabbits that have a single-compartment stomach.
"Foragers first used pottery as a revolutionary new strategy for the processing of marine and freshwater fish," said lead researcher Oliver Craig of Britain's University of York.
The pieces were found at 13 sites around Japan but mainly on the western coast of Honshu.
They are dated to a period called the Incipient Jomon, named after aboriginal foragers who inhabited the archipelago in the late Ice Age.
The fragments were found years ago, but the forensic analysis has only now provided clues about what the pottery was used for.
Pots are obviously useful for food storage and cooking. But the idea that they should be used by hunter-gatherers is controversial, because they are delicate and would seem to have no place in a tribe which is always on the move.
Many anthropologists had presumed that Jomon pottery was brought out only for special rituals or ceremonies and not used for day-to-day living.
But the new study points to a culinary use, and probably a widespread one, too.
It notes that the 13 sites were on Japan's narrow coastal plain and rivers, where there would have been an abundance of fish, marine mammals and game -- a terrific temptation for hunter-gatherers to give up life on the move.
"For a long time ceramics have only been associated with farmers, but now it is becoming clear that pottery was used by hunter-gatherers in many parts of the world," Craig told AFP in an email exchange.
"In Japan this has been known for a long time, but raises the question: why would these mobile hunter-gatherers invest time in heavy, fragile pots?
"Our research shows that [hunter-gatherer] pottery was associated with processing fish -- we suggest that these resource-rich water-edge environments meant that they could be slightly less mobile, thus freeing up time to invest in pottery production."
Demographic and social factors, as well as the changing climate, no doubt also played a role in the switch towards this half-way house.
"In Japan, agriculture (rice) was not introduced for another 10,000 years," said Craig.
"We can't just assume that agriculturalists were sedentary and hunter-gatherers mobile -- it's much more complex," he said.
"Often too much emphasis is placed on the great changes brought about by the introduction of domesticated plants and animals when hunter-gatherers were living very similar lives" to settled farmers.