April 18 (UPI) -- By measuring the changing concentration of urine salts at an archaeological site in Turkey, researchers are beginning to understand when and how hunter gatherers across the Near East began herding and farming.
Archaeologists estimate the switch from hunting and gathering to farming and herding, the so-called Neolithic Revolution, began around 10,000 B.C. But questions about exactly how and where the change came about, and how fast change swept across the region, continue to trouble scientists.
To get a better sense of the transition that inspired technological innovations and the birth of growing cities, scientists decided to study traces of ancient urine.
"This is the first time, to our knowledge, that people have picked up on salts in archaeological materials, and used them in a way to look at the development of animal management," lead researcher Jordan Abell, a graduate student at Columbia University's Lamont-Doherty Earth Observatory, said in a news release.
Abell and his colleagues tracked the changing concentrations of urine salts over a 1,000 year period, around the same time archaeological evidence suggests humans at the ancient Turkish site began domesticating animals. Their analysis showed that around 10,000 years ago, the concentration of humans and animals jumped from nearly zero to one human or animals for every 100 square feet.
Scientists can't distinguish between urine salts left behind by humans and animals, but they determined the increase in the amount of urine salts can't be explained by humans alone. There weren't enough buildings to account for such a large increase in human inhabitants.
Across the earliest layers of the settlement remains, between 10,400 to 10,000 years ago, scientists measured very few urine salts. Between 10,000 and 9,700 years ago, scientists recorded a 1,000-time increase in urine salt levels.
The findings -- published this week in the journal Science Advances -- support the hypothesis that settlers began by corralling just a few sheep and goats, but relatively quickly developed the ability to manage domesticated animals and large scale.
The new research also undermines the theory that the Neolithic Revolution had a single origin point and spread outward. Instead, the latest findings suggest the transition from hunting and gathering to farming and herding happened concurrently across a large swath of the Near East.