Ancient Proteins Unlock Secrets of Mysterious Human Relatives in China

Scientists have discovered bones and teeth in a cave in southwest China that belonged to Denisovans — a mysterious group of ancient human relatives. The remains were found at Bianfu Cave in Yunnan Province and are between 70,000 and 190,000 years old. Researchers used a special method called protein analysis to identify who these bones belonged to. The discovery helps us learn more about what Denisovans looked like and how they lived.

Denisovans are an ancient group of humans that lived thousands of years ago alongside Neanderthals and early modern humans. Until recently, scientists only had a few small fossils — mostly teeth and a finger bone — from a cave in Siberia, Russia. This new discovery in China greatly adds to what we know about them. It is one of the most important Denisovan finds in years.

The cave, called Bianfu Cave, was dug up by scientists starting in 2019. Workers found more than 64,000 animal bone pieces in the cave. Among those, researchers carefully studied over 22 bone pieces that might have come from an ancient human. Four teeth were also found, and scientists used the proteins inside them to confirm they were Denisovan.

To figure out who the bones belonged to, scientists used a technique called ZooMS, which stands for Zooarchaeology by Mass Spectrometry. This method reads ancient proteins found inside bones to identify the animal or human they came from. Think of proteins like tiny biological name tags — they stay preserved in bones for hundreds of thousands of years. By reading those tags, scientists could match the bones to Denisovans.

One of the most exciting finds was a piece of a radius — one of the two bones in the forearm. This is the first time scientists have identified a Denisovan arm bone. By studying its shape, they found something surprising: in some ways it looked like a Neanderthal arm bone, but in other ways it looked more like a modern human arm bone. This mix of features tells scientists that Denisovans may have used their arms in different ways than either group.

The four teeth found in the cave were also very helpful. Scientists compared them with Denisovan teeth found in other places, like the Xiahe jaw from Tibet and teeth found in Laos. The teeth looked very similar, which strongly suggests they all came from Denisovans. Two of the teeth were tested for proteins, and the results confirmed what scientists expected.

Scientists also used special dating methods to find out how old the cave layers were. They used light-based tests and uranium-based tests on the rocks and bones. These tests showed the cave was used between 70,000 and 190,000 years ago, making it the oldest known Stone Age site found in western Yunnan Province.

In total, 1,366 stone tools were discovered in the cave, including tools used for cutting and scraping. Along with the tools, researchers found fossils of deer, cattle-like animals, rhinoceroses, and hyenas. These clues help paint a picture of what life was like in and around the cave all those thousands of years ago.

The researchers hope that this new way of studying ancient proteins will help find even more Denisovan remains in the future. By combining protein data with bone shapes, fossil ages, and information about the environment, scientists can learn how Denisovans survived — and why they eventually disappeared. Every new bone or tooth discovered is another clue in one of history's greatest mysteries.