Neanderthals thrived in Europe for 150,000 years, but as new players with more sophisticated tools took over, their territory grew smaller. Here's a board game explanation from Nature Video. (Courtesy of Nature Video)

We know that modern humans won an evolutionary race against our Neanderthal relatives, but exactly how and when did they leave us? According to a new study published Wednesday in Nature (described in the video above), the shift may have happened quite gradually.

Using recent advances in radiocarbon dating technology, the researchers dated remains found at more than 40 archaeological sites across Europe. By accurately dating the remnants of human and Neanderthal life, they've pieced together a more complete picture of the transition.

Around 45,000 years ago, the researchers report, humans started to appear in small clusters dotted around Europe. But gradually, the balance shifted -- and over the next 5,000 years, humans began to proliferate as Neanderthals disappeared. Instead of being quickly obliterated, the Neanderthals just became less common, and soon they were the species dotted around the continent.

Tom Higham and Katerina Douka selecting samples for dating. (Thomas Higham)

While some areas lost all Neanderthals within a few hundred years, it seems that others maintained small populations, even as early humans moved in. It's not news that humans and Neanderthals interacted (and probably even interbred), but scientists had no idea that some regions experienced so much overlap.

On the other hand, the new study seems to prove that while they spent a surprising amount of time in the same place, humans and Neanderthals shared less time together on the Earth overall. While some scientists have suggested that Neanderthals held out in Iberia until less than 40,000 years ago, the new study was unable to find any evidence of such a population. Instead, the authors report, the last Neanderthals slowly took up less and less of a mosaic culture spread across Europe, giving them plenty of time to exchange ideas (and genes) with our ancestors.