In a thousand-year-old Himalayan folk tale, a king and queen, followed by their attendants, trek into the mountains of northern India聽to the shrine of Nanda Devi, the mountain goddess. But on the way, the goddess strikes the pilgrims down for their celebratory and inappropriate behavior, and they fall into small, glacial Roopkund Lake.聽
In 1942, a British forest ranger聽assigned to patrol the Indian Himalayas during the Second World War聽came across the lake and found the skeletal remains of hundreds of people. News spread, and Roopkund Lake, in the present-day Indian state Uttarakhand,聽was聽rechristened聽Skeleton Lake.聽
Thus began a now 77-year-old mystery about who these humans were, what brought them to the isolated, often frozen lake, and how they died.
The Nanda Devi tale could help explain the bodies. The pilgrimage they attempted, the Nanda Devi Raj Jat, is a three-week journey still undertaken聽today to worship the goddess. Some hypothesize that the bodies could be evidence of a fatal 19th-century military expedition, but when many women鈥檚 bodies were found in the lake, this idea fell out of favor. Based on evidence of compression fractures on a few of the humans鈥 skulls, the most common belief is聽that a hailstorm sometime between 830 and 850 A.D. 聽published Tuesday in Nature Communications, however, contradicts this聽theory.聽
In the study, researchers聽radiocarbon-dated and genetically analyzed the skeletal remains of 38 bodies found in the lake to find out how old the bones are and the individuals鈥 ancestry. They also analyzed the stable isotopes in the samples to learn more about what they ate. What the researchers聽found surprised them.聽
鈥淭he assumption was that all the skeletons dated to around the eighth century, but it became clear that this is not what happened,鈥 says 脡adaoin Harney, the lead author of聽the paper and a doctoral candidate at聽Harvard University鈥檚 department of organismic and evolutionary biology.聽The bodies in the lake, instead of dying in a single catastrophic event, range from a few hundred to a thousand years old.聽
The authors also assumed that the individuals were all from the Indian subcontinent, as this is what . But once they had the聽ancient DNA samples, 鈥渋t was clear this was definitely not the case,鈥 says Harney.聽
Genetically, the remains聽fall into three distinct聽groups, ranging from 1,000-year-old populations from聽South Asia聽to 200-year-old populations from Greece and Crete, along with one individual from East Asia. Twenty-three of the bodies analyzed were from South Asia, whereas 14 were of Mediterranean origins.聽Even those individuals from South Asia 鈥渉ave ancestry that鈥檚 really diverse,鈥 says Harney. 鈥淚t鈥檚 not a single population coming from somewhere within India.聽Instead it鈥檚 people from all over the subcontinent.鈥 聽
The results of the isotope analysis also show diverse diets within and among each subgroup, adding to the mystery.聽
As for聽how they died there and why, Harney says:聽鈥淭he only hint that we have is that Roopkund Lake is located along the pilgrimage route聽that may have been used for the last 1,000 years.鈥 And yet, for Harney, it is difficult to imagine this as the sole reason for such a genetically and culturally diverse聽set of people to die in聽the same remote lake.聽
鈥淲e鈥檙e still pretty puzzled,鈥 she says,聽and more research is needed to determine the exact nature of these deaths. A massive hailstorm still can鈥檛 be ruled out, but the scientists wonder if the hailstorm was the fatal blow or if it occured聽after the people died.
And compared to other archeological sites, Roopkund is challenging to study. 鈥淚t鈥檚 been subject to so much disturbance, both from the natural environment, like rockslides,鈥 says Harney, and from hikers on the nearby trail going down to retrieve bones or look at the site.聽
The study does highlight聽the ways in which humans have traveled聽to far-off places聽for hundreds, if not thousands,聽of years.聽鈥淲e knew that there were long-distance connections,鈥澛爏ays Harney,聽but the new knowledge demonstrates 鈥渉ow important migration and connections between different parts of the world have been throughout history.鈥