Researchers Discover Rare Denisovan Bones in a Cave in China

For many years, scientists knew Denisovans mainly from their DNA, extracted from a fossilized pinkie bone found in a Siberian cave. Since then, a few more bits and pieces have been found, including a rib, a few teeth, and two jaw fragments. The biggest discovery came last year when researchers identified the heavy-browed “Dragon Man” skull, previously found in northeastern China, as belonging to a Denisovan. Nevertheless, the extinct ancient humans remain elusive, and scientists have struggled to link their fossils to nearby stone tools or animal bones.

Now, two international teams of scientists have announced the discovery of three Denisovan bones, four teeth, and more than 1,360 stone tools at a site called Bianfu Cave in Yunnan Province, southwestern China. The fossils include two skull fragments and the first Denisovan forearm bone. The remains and stone tools were found among more than 60,000 mammal bone fragments.

The findings, which were detailed Wednesday in two papers in Nature, finally allow researchers to browse a collection of tools—including scrapers, choppers, hammerstones, and bone tools used to shape them—left lying around by Denisovans over the course of their daily lives.

“We have many sites, but we often don't know who is the maker of these tools,” says Hao Li, an archaeologist from the Institute of Tibetan Plateau Research in Beijing, and an author of one of the papers. With their new discovery, Li and the researchers have now made a strong connection between Denisovans and the stone tools they created and used. Many of the tools and animal remains found at the cave bear marks that Li says likely resulted from being rubbed or banged together.

“I am fascinated by the insights into the technology used by Denisovans,” says Svante Pääbo, an evolutionary geneticist from the Max Planck Institute for Evolutionary Anthropology in Germany. Pääbo’s lab sequenced the first Denisovan DNA from the finger bone in 2010, but he was not involved in the new study. “It is wonderful that we are finally getting some direct insights into how they lived.”

(Scientists discovered a new kind of human with its pinkie bone. Now we have a skull.)

Pääbo adds that although the researchers identified the remains as Denisovan based on limited data, “it is the best that can be done and I am quite convinced that these are Denisovan remains.”

Specifically, since no DNA could be extracted from the remains, the researchers had to find another way to identify them. They did so by examining a collagen protein common in bone that varies slightly in amino acid composition across hominins. For the researchers, the results left little doubt that the bones are Denisovan.

The bones date to between 167,000 and 134,000 years ago, while the tools span an even wider range from 190,000 to 70,000 years ago, says Qingfeng Shao, a geochronologist from Nanjing Normal University in China who contributed to both studies. He adds that the discovery was a lucky one, as it occurred during a project to restore vegetation in a former limestone quarry.

“Most of the cave had already been destroyed,” Shao says.

Perhaps most remarkable about the Denisovan skull fragments is their thickness—0.3 to 0.4 inches—which is more like that of Homo erectus (our common ancestor) and Neanderthals than of modern humans.

The recovered forearm bone is part of the radius, which extends from the thumb side of the wrist to the elbow. Only the elbow side of the bone was preserved, revealing that in Denisovans the biceps attachment point was shifted farther back on the bone than in modern humans. That finding suggests that for the same muscle size, Denisovans could generate more force when twisting their arms into a palm-up position than modern humans can.

The tools suggest a rather impromptu approach to toolmaking, as they had not been worked to the extent seen in some archetypal Homo sapiens tools. In many cases, it seems Denisovans may have just knocked a couple of sharp flakes from a stone, used them, and then abandoned them, says Li. The tools found at the site suggest Denisovans were not as invested in a particular shape or technique as our own ancestors would become.

Perhaps they didn’t need to be, as the plentiful remains of animals like deer and buffalo suggest food wasn’t too hard to get in the relatively mild environment of the region, even during the Ice Ages that occurred across the period from which Denisovan remains were recovered. But it may help explain why Denisovans were outcompeted when Homo sapiens appeared on the horizon.

(Inside the hunt for the other humans)

Denisovans didn’t entirely disappear, however. The DNA of many people alive today contains evidence that their ancestors interbred with Denisovans. Tibetans acquired a gene this way that helps them survive at high altitudes. Denisovan heritage is common among Indigenous peoples in places like the Philippines, Papua New Guinea, and Australia, but it also occurs in many other people around the world. 

The recent discovery of Denisovan remains in southwestern China now reveals that they occurred far beyond the remote northern regions where they were first discovered and may have met and mingled with our own ancestors much farther south.

“I am impressed by both studies, and happy to see another locality that can provide insights into the archaeological signature of Denisovans,” says Frido Welker, an expert in ancient protein analysis from the University of Copenhagen who was part of a team that identified a Denisovan tooth from Laos, but was not involved in this study. “I think this is incredibly important for furthering our understanding beyond their genetic impact on modern human genomes.”