for National Geographic News
Traces of ancient horse manure have been found in a remote 5,600-year-old Kazakh village—a discovery that could be the earliest known evidence of horse domestication.
A team of archaeologists and geologists discovered the traces inside a circular array of postholes in the village.
While no actual smelly remains were present, the researchers did find that the level of nutrients called phosphates was ten times higher in the soil within the array than in soil adjacent to it.
Animal manure is high in nutrients, including phosphates, so the find is a strong indication that the enclosure used to be a corral.
The village, called Krasnyi Yar, was inhabited at the time by the Botai culture of the Eurasian steppes (map of Kazakhstan).
These people are believed to have relied heavily on horses for meat, tools, and transport.
Andrew Stiff, a graduate student at the University of Pittsburgh in Pennsylvania, presented the findings this week at the annual meeting of the Geological Society of America in Philadelphia, Pennsylvania.
In addition to phosphates, animal manure is high in nitrates. But elevated levels of nitrates were not found within the enclosure.
Team member Rosemary Capo, a professor at the University of Pittsburgh, says the lack of nitrates supports the theory that the manure evidence dates back more than 5,000 years.
Nitrates easily leach out of soil during rainstorms or are decomposed by bacteria, she notes, while phosphates can remain for millennia.
So the lack of nitrates indicates that the researchers didn't simply find evidence of a later animal enclosure built on the same site.
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