High-altitude cave used by Tibetan Buddhists yields a Denisovan fossil

The Denisovan diet

The ZooMS analysis showed that a lot of species eventually met their end in the Baishiya Karst Cave or were at least dragged there after dying. The single most common species was a bharal, or blue sheep, which is widespread across the Himalayas. But yaks, horses, and gazelles also appeared, along with two species of deer. These are consistent with the open grasslands near the site at present, but also suggest there may have been some small patches of wooded shrublands present as well.

There was also a range of smaller and larger species, including a woolly rhinoceros, flying squirrels, and porcupines. Predators included the spotted hyena, wolf, and snow leopard, and birds like the pheasant and golden eagle.

Obviously, some of these are extremely unlikely to have ended up in a cave on their own. But characterization of the bones show that many of them have signs of muscle being cut away and/or having been broken open to extract the marrow. Combined, rodent and predator damage appear on only 1 percent of the bones, while clear signs of butchering are present on nearly 20 percent. A handful also show signs of being worked into tools.

The lack of predator damage suggests that, in many cases, the people who occupied the cave weren't simply scavenging someone else's kills to get their food. In addition, the frequency of the species changes over time, with an increasing number of sheep in the more recent layers, suggesting that the Denisovans there were becoming more specialized hunters.

Another Denisovan bone

One of the bones didn't belong to any of the groups mentioned above. Instead, it clearly belonged to a human relative. Careful collagen sequencing from the bone showed that it clustered in with Denisovan populations found elsewhere, making it one of the larger bone samples we've ever obtained from them. Unfortunately, it's still just a fragment of a rib that's only 5 centimeters long.

Intriguingly, the bone came from a layer within the cave where environmental DNA hadn't indicated the Denisovans were present. Whether this is a matter of the Denisovans having become less frequent visitors or a matter of the preservation of environmental DNA isn't clear. But it does indicate the Denisovans were present on the Tibetan Plateau as recently as 30,000 years ago.

So, while we've learned a bit more about these relatives of ours, we still have no idea what they looked like. And any plants in their diet weren't preserved in the cave, so the study only provides a partial picture of their eating habits.

Still, the finds show that the Denisovans lived in a harsh, high-altitude climate over two distinct glacial periods, indicating that they were very adept survivalists. And it appears that they passed at least one of the things that helped them handle the altitude on to the present-day inhabitants of the Tibetan Plateau.

Nature, 2024. DOI: 10.1038/s41586-024-07612-9  (About DOIs).