Ancient DNA reveals unknown yak-like Ice Age mammal in Siberian Denisova Cave

A team led by evolutionary geneticist Love Dalén analyzed twenty fragmented bones from Denisova Cave, the same site that yielded Denisovan human remains, and recovered ancient DNA that defines a previously unknown large bovine species. The DNA shows the animal diverged from the ancestors of today’s yak around 400,000 years ago, and the sampled specimens date from roughly 250,000 to 27,000 years ago. Because the fragments are too small to identify morphologically, the researchers coined the provisional name “Yak X” until a formal taxonomic description can be made.

The species likely resembled a yak more than a bison and shared the mammoth-steppe ecosystem with steppe bison, aurochs, woolly mammoths and predators such as cave hyenas. Population analysis hints at a decline during a warming episode about 120,000 years ago, with extinction occurring after the youngest sample. The discovery broadens understanding of Ice Age biodiversity and suggests Yak X may have been part of the Denisovan diet.