A timeline of cave dwellers in sediment Two archaic lineages overlapped with modern humans outside of Africa: the well-studied Neanderthals and their more mysterious cousins, the Denisovans. Denisovan remains are rare, being limited to Denisovan Cave in Siberia and a putative, undated jaw from Tibet. However, there is evidence for multiple introgressions from Denisovans into modern-day humans, especially in Australasian populations. By examining the sediment of Baishiya Karst Cave located on a high plateau in Tibet, Zhang et al. identified ancient mitochondrial DNA from Denisovans indicating their presence at about 100 thousand, 60 thousand, and possibly 45 thousand years ago. This finding provides insight into the timing and distribution of Denisovans in Asia and extends the time of occupation of the Tibetan plateau by hominins. Science , this issue p. 584