This breakthrough DNA technique allows researchers to examine entire past ecosystems without relying on bones or other artifacts.

Some 19,000 years ago, a 35-to-40-year-old woman, coated in red ochre, was buried in a cave in what is now northern Spain. This was a tough time for her people, likely still recovering from the last glacial maximum. Nicknamed the "Red Lady" due to her ochre-coated bones, she was a member of the Magdalenian people of the late Upper Paleolithic -- people not so unlike us.

Fast-forward to 2010, archaeologists uncovered her remains in what is now called El Mirón Cave, providing a vital glimpse into this little known era of human prehistory. Now the same scientists who discovered her remains and subsequently reported on the discovery in 2015 are providing even more context related to the lineage of this unknown woman by analyzing a new kind of DNA. Called sedimentary ancient DNA or sedaDNA, this technique allows scientists to understand the various inhabitants of El Mirón Cave spanning some 46,000 years without the need to directly analyze bones or other artifacts. The results of the study were published in the journal Nature Communications.

"The results show that several animals not represented by bones from the dig were present -- either once living in the cave or as carcass pieces," the University of New Mexico's Lawrence Straus, who originally discovered the 'Red Lady' in 2010 and co-authored the new study, said in a press statement. "As with everything else at El Miròn DNA-wise, the preservation of DNA in dirt here is extraordinary."

These previously unmentioned animals, at least in the fossil records, include cave hyenas, leopards, cave lions, and, surprisingly, a species of dhole that's now only found in parts of Asia. They also found some larger species of hoofed animals as well, including wooly mammoth, reindeer, and rhinoceros.

However, the most fascinating discovery is that the team also found human DNA belonging to the 'Fournol' genetic ancestry, a Western European hunter-gather group that lived during the height of the last glacial maximum around 25,000 to 21,000 years ago. Incredibly, the researchers tied this DNA with similarities found in the Red Lady's DNA as well.

"These were the people whose range had contracted southward during the climatic crisis and who preceded the Red Lady of El Miron and contributed to her DNA," Straus says. "We now know who the predecessors of the Red Lady were, confirming evidence from other sites with DNA from bones and teeth."

The ability extract DNA from sediment layers, particularly at a site like El Mirón Cave, give scientists the ability to examine human-animal habitation cycles as well as entire environments without the need of physical remains. Because of its 46,000 years of unbroken DNA information, archeologists can peer back into a time when Homo neanderthalensis occupied the area all the way up to modern Homo sapiens in the Upper Paleolithic.