BRISTOL, England, Jan. 27 (UPI) -- By grinding up millennia-old pottery, scientists have detected traces of milk some 6,000 years old in Britain, the earliest direct evidence known of human dairy activities.
The finding reveals not only that milk did prehistoric Britons' bodies good, but it also promises to help archaeologists unravel more about ancient economies and health and learn how farmers replaced hunter-gatherer societies.
"We're now using the techniques we applied in Britain to look at the very origins of dairying in the Fertile Crescent in the Near East, the very heart of agriculture," biogeochemist Richard Evershed of the University of Bristol told United Press International. "Through this we get a time capsule about the activities of our forefathers."
Scientists have long known humans first began raising livestock at least 10,000 years ago. What archaeologists have disputed for the past 30 years, however, is the point at which early civilizations learned to domesticate animals not solely for their meat but also for their milk and wool, explained zooarchaeologist Marie Balasse of the National Museum of Natural History in Paris.
"Milking is quite an advance because it is highly nutritious. It dramatically changes the number of people you can sustain instead of simply slaughtering prized animals for meat," Evershed explained. "It's not at all clear when it happened by looking at the archaeological record."
Evershed and colleagues earlier discovered milk and meat fatty acids differ atomically. When it comes to carbon-13, which contains seven neutrons in its nucleus, milk has about one-fiftieth less carbon-13 in its fats than meat, due to metabolic differences in how livestock species create each fat type.
Fatty acids often get absorbed deeply into ceramics, where they are protected against the damage of time. Evershed and his team collected nearly 1,000 pottery shards from 14 archaeological sites in Britain dating back to the Stone, Bronze and Iron Ages, then pulverized them and bathed them in solvents to search for milk residues.
In findings published online Jan. 27 by the Proceedings of the National Academy of Sciences, the researchers discovered dairy residues millennia old. This is the first direct evidence milk was consumed by humans in the early Neolithic, or Stone Age, Balasse said. Until now, the only evidence for dairying in Neolithic Europe consisted of perforated jugs that resemble cheese strainers. Rock art portraying milking also is found in Africa, although the drawings have not yet been dated.
The milk findings could help reveal the genetic impact dairying had during the origin of civilizations.
"It would have set up a nutritional factor that selected for people who could tolerate lactose as adults," said archaeologist Stanley Ambrose of the University of Illinois at Urbana-Champaign. "People who could digest lactose probably had more babies than people who didn't. That could have been very important in the past. The people who drank milk could outlast you, especially in tough times of the year when food was limited."
(Reported by Charles Choi, UPI Science News, in New York)
