Ancient DNA reveals 'Yak X', a lost Ice Age cousin of modern yaks

Scientists have identified 'Yak X', a previously unknown Ice Age bovine related to today's yaks, using ancient DNA from 20 bone fragments, 14 of them from Siberia's Denisova Cave. The study in Current Biology says its lineage split from modern yaks' ancestors about 400,000 years ago. It lived alongside woolly mammoths and woolly rhinos in the Altai Mountains.