Animal domestication in Central Asia goes back at least 8,000 years — nearly three millennia earlier than previously thought — according to new research, making the area one of the oldest continuously inhabited pastoral regions in the world.

Previous archeological evidence suggested that an agropastoral economy was introduced to interior Central Asia around 3,500 B.C., which would've been a relatively late arrival compared to other parts of the ancient world. Using archaeological and biomolecular evidence from Obishir V, a rock shelter in southern Kyrgyzstan, researchers found that domesticated animals such as sheep and goats were likely in the region as early as 6,000 B.C.

Central Asia has served as a crossroads for people and culture since the Silk Road, in large part because of economic developments driven by the availability of domesticated animals. When these animals arrived in the region, however, has remained largely unclear. Soviet-era archaeologists hypothesized that agropastoralism arrived in southwest Asia sometime between the fourth and seventh millennia, but evidence of this was limited because of fragmentary and inconclusive archaeological data sets. 

Obishir V, the Holocene rock shelter located in the Inner Asia Mountain Corridor, was first identified in 1965 and excavated throughout the 1960s and 1970s, with renewed interest in 2015. 

Svetlana Shnaider, of the Institute of Archaeology and Ethnography of the Siberian Branch of the Russian Academy of Sciences, led an excavation of Obishir V, and came to William Taylor, an assistant professor and curator of archaeology at the University of Colorado Museum of Natural History, with fragmented animal bones she found at the site. Shnaider believed the bones came from domesticated sheep and goats, which meant these animals were in the area many thousands of years before researchers had expected. 

The fact that they were able to confirm this discovery is largely due to improvements in the technology used in archeological analyses, Taylor said.

"The problem is that until really recently, archaeologists didn't have a lot of tools to identify domestication in the archeological record," he said. "Animal domestication is essentially a relationship, and what we're left with after 8,000 years is often just a handful of fragments, and so as a result of that, there are regions and entire time periods where the archeological record might be thinner than usual."

The researchers had a total of 400 animal bone fragments. Of these, 24 were morphologically identified as Ovis, a genus of mammals that includes sheep or Capra, a genus that includes goats. Eighty-nine were identified more broadly as ungulates, or mammals with hooves, and the rest weren't identifiable to a taxonomic class. 

Using the animal's teeth, specialist William Rendu conducted a cementum analysis, which found that all of the animals had died in the fall, consistent with the practice of seasonal culling done by many herders of the time.

Standard kinds of zooarchaeological analyses wouldn't have been helpful in learning more specifics given the fragmented state of the bones, so the researchers turned instead to biomolecular methods to test whether the animals were wild or domesticated. The researchers compared the sequenced genomic material from the ancient sheep and goats with genomes from modern domestic sheep and goats in Eurasia and Africa, as well as wild Asiatic mouflon. The Obishir V sheep were most similar to modern Southwest and Central Asian sheep breeds and mitochondrial haplogroup A, which is one of the oldest haplogroups for domestic sheep in the region.

There are still unanswered questions about whether the animals were accompanied by people moving into the region from areas like Mesopotamia and Africa, whether the animals could be found in other locations in Central Asia or whether domesticated plants were also in the region as early as 6,000 B.C. Taylor said he and his fellow researchers are now working on finding the answers to the new questions this finding has raised. 

"One of the most exciting things about this finding is that it probably raises more questions than it answers," Taylor said. 

This discovery has important implications for understanding the history of transcontinental connections and domestic animal movements, he said, and it means that the entire fabric of landscapes, ecology, culture and economy from Central Asia has grown out of the relationship between people and domestic animals.

"Recognizing that the relationship between people and domestic animals in Central Asia was not just this recent development but was more than 8,000 years old makes it one of world's oldest continuously inhabited landscapes," Taylor said. "For me, it was really startling to realize the antiquity of that relationship. It forced me to rethink how I view the importance of that relationship between people and livestock."

The study "Evidence for early dispersal of domestic sheep into Central Asia," published April 8 in Nature Human Behavior, was authored by William Taylor, University of Colorado-Boulder and Max Planck Institute for the Science of Human History; Mélanie Pruvost, Université de Bordeaux; Cosimo Posth, Max Planck Institute for the Science of Human History and University of Tübingen; William Rendu, Université de Bordeaux and Institute of Archaeology and Ethnography SB RAS; Maciej T. Krajcarz and Greta Brancaleoni, Polish Academy of Sciences; Aida Abdykanova and Ludovic Orlando, American University of Central Asia; Robert Spengler, Taylor Hermes, Raphaela Stahl and Katerina Douka, Max Planck Institute for the Science of Human History; Stéphanie Schiavinato, Université Paul Sabatier; Gregory Hodgins, University of Arizona; Jina Min and Choongwon Jeong, Seoul National University; Saltanat Alisher kyzy and Andrey Krivoshapkin, Institute of Archaeology and Ethnography SB RAS and Novosibirsk State University; Stanisław Fedorowicz, University of Gdańsk; Christina Warinner, Max Planck Institute for the Science of Human History and Harvard University; and Svetlana Shnaider, Institute of Archaeology and Ethnography SB RAS.