Fragments of bones were found in Siberian caves, allowing scientists to discover a long-lost relative of the modern yak. These findings provide insight into an animal from the Ice Age that existed hundreds of thousands of years before disappearing.
Researchers analyzed ancient DNA extracted from twenty fragmented bones found in locations such as Denisova Cave in Southern Siberia. The genetic data revealed a previously unknown lineage of cattle, nicknamed 'Yak X,' which inhabited the region approximately between 247,000 and 27,000 years ago.
This discovery is significant because many of the bones are too damaged to be identified by appearance alone; however, their DNA preserved a much clearer history.
Genetic analysis shows that 'Yak X' began to diverge from the ancestors of modern yaks about 400,000 years ago, and by approximately 250,000 years ago, it was largely separated from them.
The animal likely survived major climatic changes in Siberia, including a period of noticeable warming. Scientists believe that changing conditions may have contributed to population isolation and directed them down different evolutionary paths.
'Yak X' was not alone in this region. Its remains were found alongside evidence of other Ice Age animals, such as the steppe bison and aurochs, an extinct wild ancestor of modern cattle. Despite coexisting with other large bovines, genetic data indicates minimal interbreeding of 'Yak X' with them.
This discovery adds a new layer of information to the history of Denisova Cave, which is already known for the discovery of remains of an ancient human group—the Denisovans. Now, the cave helps reconstruct another lost chapter of the region's past, piece by bone fragment.
The exact time and cause of 'Yak X''s disappearance remain unknown to scientists. The youngest remains date back to approximately 27,000 years ago, but researchers believe more evidence is needed to determine its final fate. There is also a possibility of a connection between 'Yak X' and a previously described fossil animal known as the Baikal yak, although this link has not yet been confirmed.
It is noteworthy how easily this animal could have remained unknown. Its bones were broken and difficult to identify, but they contained enough ancient DNA to reveal an entire branch of the cattle family tree. Sometimes the smallest fragments of the past can tell the biggest stories.