Scientists have long debated when humans and human ancestors started to dominate the natural world—a milestone in human history. New research suggests Neanderthals' activities turned a forested area into grasslands nearly 125,000 years ago, providing the oldest evidence of land-altering behavior in ancient humans yet, New Scientist reports.
Neanderthals lived along the edges of lakes and forests a site called Neumark-Nord near Halle, Germany. At some point during their residence, open spaces began to emerge within the forests, according to a press release.
"The question is, of course, whether it became open because of the arrival of hominins, or whether hominins came because it was open?" lead author Wil Roebroeks, an archaeologist at Leiden University in the Netherlands, says in a press release. "However, we have found sufficient evidence to conclude that hunter-gatherers kept the area open for at least 2,000 years."
Researchers analyzed pollen, fossils, tools and charcoal deposits from Neumark-Nord, helping piece together what the landscape looked like and how Neanderthals occupied it, Bruce Bower reports for Science News.
As part of their analysis, the team mapped out where Neanderthals lived and compared it with pollen and charcoal samples, which show what plants grew there and where fires were started. The data revealed that grass grew in inhabited areas, despite the surrounding region being heavily forested, New Scientist reports.
Plus, evidence such as stone tools, bones, wood and seeds were oftentimes charred, suggesting that Neanderthals frequently used fire in their settlements, Science News reports.
Though the evidence suggests that Neanderthals manipulated their environment, the team is still unsure how forests turned into grasslands. There was an uptick in the presence of charcoal when Neanderthals moved into Neumark-Nord, so "it’s really tempting to imagine that that might have been Neanderthals burning the vegetation," but precisely matching up the dates is tricky business, co-author Katherine MacDonald, an archaeologist at Leiden University, tells New Scientist.
It's also difficult to tell the difference between a collection of small fires—like campfires—or large ones. But setting fires, hunting, building tools and making shelters all have large environmental impacts, which affected the landscape, Science News reports.
"It also adds something to the behavioral spectrum of early hunter-gatherers," Roebroeks says in the press release. "They weren’t simply 'primal hippies' who roamed the landscape picking fruit here and hunting animals there. They helped shape their landscape."
Some scientists suspect that humans started deforesting land about 10,000 years ago to make room for fields, but others say that this started much earlier at a smaller scale. This study is now the oldest evidence of hominids reshaping their environment, and Roebroeks expects scientists to find even earlier evidence, he says in the press release.