No bones? Don't worry, modern scientists will still be able to study the DNA. According to a report from Phys Org, a team of researchers from Max Planck Institute for Evolutionary Anthropology has actually found a new way of retrieving hominin DNA from cave sediments even without surviving fossils.

The group collected sediment samples ranging from 14,000 to more than 550,000 years old from seven different archaeological sites in Belgium, Croatia, France, Russia and Spain. From these samples, they managed to recover tiny DNA fragments. The DNA belonged to a variety of animals such as the woolly mammoth, the woolly rhinoceros, the cave bear and the cave hyena.

More significantly, there were sediment samples that featured DNA of ancient human origins. Eight samples had Neanderthal DNA while one contained Denisovan DNA.

"By retrieving hominin DNA from sediments, we can detect the presence of hominin groups at sites and in areas where this cannot be achieved with other methods," co-author Svante Pääbo of the Max Planck Institute explained. "This shows that DNA analyses of sediments are a very useful archaeological procedure, which may become routine in the future."

According to a report from New Scientist, environmental DNA found in samples of soil or water are becoming an increasingly powerful tool when it comes to studying ecosystems. Environmental DNA can last for up to 700,000 years in sediments buried in cool caves and in permafrost.

Researchers are now planning to see if there are surviving DNA in sites where fossils have never been found. Although cave sediments are difficult to date, the potential for learning more about ancient human ancestors are vast.

Lead author Viviane Slon pointed out that their new method could be useful in sites where stone tools have been unearthed, but no one knows who made and used them. The findings were published in the journal Science.