Inside a cave beneath a medieval German castle, researchers have discovered a pit of bones that they say unlock secrets of the earliest humans.
The remains — buried in layers of soil in the collapsed cave — contained the genetic material of cave bears, hyenas and 13 bones of early humans who died some 45,000 years ago.
The findings — which were described in a trio of papers published Thursday in the journals Nature and Nature Ecology & Evolution — show that early humans ventured further north earlier than scientists had realized, that they could craft spear-shaped tools, and that humans then had the wherewithal to thrive in temperatures far more frigid than the climate today.
The discoveries, which were made possibly because of the development of new DNA technology, are reshaping how scientists understand the time when both humans and Neanderthals walked the European continent.
“Because of the age of this site and location, we know Neanderthals and humans quite definitively had a large overlap,” said Elena Zavala, a paleo and forensic geneticist at the University of California, Berkeley, who helped author the three studies. The species likely roamed the same geography for hundreds, perhaps thousands, of years.
The discoveries could bring scientists closer to understanding why Neanderthals ultimately died out and what role humans played in their demise.
John Hawks, a University of Wisconsin-Madison paleoanthropologist who studies ancient human relatives but was not involved in this research, said the study helps solidify the theory that patches of different human cultures were developing as Neanderthals neared their end.
“These groups are exploring. They’re going to new places. They live there for a while. They have lifestyles that are different,” he said of the early humans. “They’re comfortable moving into areas where there were Neanderthals.”
These discoveries were only possible because previous researchers left a stone unturned. Archaeologists in the 1920s and 1930s previously excavated the Ilsenhöhle cave, below the Ranis Castle in Germany’s Thuringia region. The castle was built above the cave long before any excavation.
At that time, the scientists hit a more than 5-foot-thick rock, which blocked them from burrowing into key layers of the collapsed cave.
In 2016, armed with modern digging technology and new forms of analysis, the researchers returned. About 24 feet below the surface, they found layers that contained leaf points — which are like spear points — and human bone fragments.
The discovery of human bone fragments sent the researchers digging through the material excavated about nine decades ago — in which they found additional skeleton fragments.
“Finding human remains mixed with animal bones that had been stored for almost a century was an unexpected and fantastic surprise,” Hélène Rougier, a palaeoanthropologist at California State University Northridge, said in a news release.
In all, the researchers were able to identify 13 pieces of bone. DNA analysis confirmed the bone fragments were from humans and also that some were linked to the same person or a family member. Tests of animal bones found nearby suggest that the climate was harsh — comparable to modern-day Siberia.
That means humans were having success in an extreme climate some 45,000 years ago.
“These early modern people seem to have mastered or put together a cultural package that let them succeed at northern latitudes better than Neanderthals had done,” Hawks said.
The study also suggests that the leaf point technology scientists had once attributed to Neanderthals was used by humans.
“It’s a thoroughly skilled process to make those things,” Hawks said of leaf points, which are flakes of rock thinned into the shape of an olive leaf. “The fact that people invested the energy to make that beautiful thing — tells us about their social system. It tells us they were not living hand to mouth. They had time to invest.”
The fate of Neanderthals has been a subject of hot debate. Did a shift in climate doom them? Did humans kill them off? Did they simply get absorbed into humanity as the species interbred?
Today, depending on their ancestry, many people still have a sliver of Neanderthal DNA in their genetic code.
More complicated genetic testing of the Ranis bone fragments, a project that is underway, could identify whether there are traces of Neanderthal genes in the recently discovered bone fragments.
“The big question — is there Neanderthal DNA? Did these humans potentially intermix with Neanderthals?” Zavala said.
Answers to questions like these in Ranis could help answer the questions intrinsic to our species’ existence, the researchers say.
“It goes after this question — what makes us human. 100,000 years ago, throughout the globe, there were multiple kinds of hominins on the planet,” Zavala said, referring to mankind’s close genetic relatives.
“Now, it’s just us. Why did that happen? How did evolution get to where we are and what does that mean for our future?”
This article was originally published on NBCNews.com