The studies have uncovered when Neanderthals and their enigmatic cousins, the Denisovans – occupied Denisova Cave in Russia, the only site in the world known to have been occupied by both groups of hominins and by modern humans at various times.

For the first time, the studies put a timeline on when Denisovans and Neanderthals were present at the site and the environmental conditions they faced before going extinct.

Denisovans, who were only discovered recently, lived at the same time as Neanderthals and modern humans roamed the Earth, but were genetically different from both.

The findings, published in Nature today, are the result of many years of detailed investigation by a multi-disciplinary team of researchers from Russia, Australia, Canada, Germany and the United Kingdom.

The new studies show that hominins occupied the site almost continuously through relatively warm and cold periods over the past 300,000 years, leaving behind stone tools and other artefacts in the cave deposits.

Fossils and DNA traces of Denisovans are found from at least 200,000 to 50,000 years ago, and those of Neanderthals between 200,000 and 100,000 years ago.

One of the studies, led by Professor Zenobia Jacobs, an Australian Research Council (ARC) Future Fellow at UOW, involved optical dating of the cave sediments, most of which are too old for radiocarbon dating.

Optical dating measures the time since quartz or feldspar grains in the sediment were last exposed to light.

Denisova Cave is situated in the foothills of Siberia’s Altai Mountains and has been excavated for the past 40 years by archaeologists from the Institute of Archaeology and Ethnography in Novosibirsk.

“This new chronology for Denisova Cave provides a timeline for the wealth of data generated by our Russian colleagues on the archaeological and environmental history of the cave over the past three glacial–interglacial cycles,” Professor Jacobs said.

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Professor Richard ‘Bert’ Roberts, a co-author of both papers and director of the ARC Centre of Excellence for Australian Biodiversity and Heritage headquartered at UOW, said the studies broadened our understanding of the cave’s ancient inhabitants, but there was still a lot to learn.

“While these new studies have lifted the veil on some of the mysteries of Denisova Cave, other intriguing questions remain to be answered by further research and future discoveries,” he said.