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Denisovans lived and thrived on the high-altitude Tibetan plateau for more than 100,000 years, according to a new study that deepens scientific understanding of the enigmatic ancient people first identified in 2010.
Researchers analyzed thousands of animal bone fragments found in the Baishiya Karst cave, 3,280 meters above sea level near the city of Xiahe in China’s Gansu province – one of three known places where the extinct people lived. Their work showed that Denisovans could hunt, butcher and process a variety of different large and small animals, including woolly rhinoceros, blue sheep, wild yaks, marmots and birds.
The team of archaeologists working in the cave also uncovered a fragment of a capillary bone in a layer of sediment dating back between 48,000 and 32,000 years, making it the youngest of the handful of known Denisovan fossils – a clue that the species was around on it recently than it was. scientists previously thought.
Due to the paucity of fossil evidence, details of how these ancient ancestors lived have been scarce. But the new study shows that the Denisovans who lived in the Baishiya Karst Cave were extremely resilient, surviving in one of the world’s most extreme environments during warmer and colder periods and maximizing various animal resources available in the grassland landscape.
“We know that the Denisovans lived, that they lived in the cave and on this Tibetan plateau for a long time, we want to know, how did they live there? How did they adapt to the environment?” said Dongju Zhang, an archaeologist and professor at Lanzhou University in China and co-lead author of the study published Wednesday in the journal Nature.
“They used all these animals that were available to them, which means their behavior is flexible,” Zhang said.
The ribs belonged to a Denisovan and probably lived at a time when modern humans were spreading across the Eurasian continent, said study co-author Frido Welker, an associate professor at the Globe Institute’s Biomolecular Paleoanthropology Group at the University of Copenhagen. . He said that future research on the site and in the region could shed light on whether there was interaction between the two groups.
“It puts this fossil and the (sediment) layer in a context where we know in the wider region that people would probably have been present, and that’s interesting,” he said.
Trace Denisovan clues
Denisovans were first identified just over a decade ago in a laboratory using DNA sequences extracted from a tiny fragment of a finger bone. Since then, less than a dozen Denisovan fossils have been found around the world.
Most of these were found in the Denisova Cave in the Altai Mountains of Siberia, which is how the group got their name. Subsequent genetic analysis revealed that the Denisovans, like Neanderthals, had once interbred with modern humans. Traces of Denisovan DNA found in humans today indicate that the species is probably ancient and once lived throughout much of Asia.
It wasn’t until 2019, however, that researchers identified the first Denisovan fossil from outside the named cave.
A jawbone with teeth discovered by a monk in the Baishiya Karst Cave, a holy place for Tibetan Buddhists, dating back at least 160,000 years and bearing a Denisovan molecular signature. The discovery of DNA from sediments at the site, published a year later, provided further evidence that Denisovans once called the area home.
In 2022, scientists identified a tooth uncovered at a cave in Laos as a Denisovan, a clue that placed the species in Southeast Asia for the first time. Like the jawbone, DNA could not be removed from the tooth, so researchers instead study the microscopic remains of proteins, better preserved than DNA, although they are less informative.
The study published on Wednesday examined more than 2,500 bits of animal bone found during excavations at Baishiya cave in 2018 and 2019.
Most of the fragments were too small to identify by eye, so the researchers turned to a relatively new technique called Zooarchaeology by Mass Spectrometry (ZooMS), which allows scientists to extract valuable information from specimens that may have been forgotten in the past.
Based on small differences in the amino acid sequence of the collagen preserved within the bone, ZooMS helped the researchers determine what type of animal the bones belonged to.
Baishiya’s place in the Denisovan story
In addition to large and small herbivores, the analysis revealed carnivores such as hyenas. Some of the animals, such as the blue sheep, are still common in the Himalayas today.
Many of the bones had cut marks indicating that the Denisovans were processing the animals for their hides as well as meat and bone marrow. Some bones were also used as tools, according to the study.
Taken together, the variety of animal species found suggests that the area around the cave was dominated by a grassy landscape with some small wooded areas – similar to today, although Zhang noted that the majority were domesticated jackals and goats. animals that live there today.
During the laborious process of categorizing the bones, which took several months, the team identified the rib bone fragment, which is 5 centimeters long. However, the resolution of the protein information was not clear enough to immediately determine what type of person it belonged to. Further analysis of the preserved ancient proteins led by Welker revealed that it was Denisovan.
The rib bone came from a layer of sediment from which the team had previously extracted Denisovan DNA, and Zhang said the researchers are trying to recover DNA from the new specimen. That process could provide more detailed genetic information about the owner of the rib and the wider Denisovan population that once lived in the area.
With so much information about the Denisovans, “every discovery is really important” and the zooarchaeological analysis by the authors of the new study was “especially revealing,” said archaeologist Samantha Brown, Junior Group Leader for Palaeoproteomics at the University of Tübingen in Germany. who worked on remains from Denisova Cave.
“The young age of the fossil is certainly surprising. At this time period we have evidence of modern humans occupying sites all the way (to) Australia. This really opens up conversations about the possibility of these groups interacting as modern humans moved into Asia and the Pacific but more evidence is likely needed to understand the nature of those interactions,” said Brown, who was not involved in the research.
Work continues at Baishiya Karst Cave, and Zhang is excavating another paleolithic site in the region that could have been occupied by the Denisovans or the modern humans who came after them, she said.
Unlike Denisova cave, which was occupied by humans and early modern Neanderthals as well as Denisovans, the current evidence suggests that Denisovans were the only group of people who lived in Baishiya Karst Cave, which Zhang said. This makes the Tibetan plateau – an area nicknamed the “roof of the world” – a very significant location in the attempt to answer the many remaining questions about who the Denisovans were, what they looked like, how They are gone and their place is on the person. Genealogy Championship.
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