Neandertals, our closest evolutionary relatives, went extinct roughly 30,000 years ago after sustaining a large population throughout Europe for at least 100,000 years. But, there is still debate about why they suddenly died out. Some say it was climate change, some say disease may have been the cause, others believe it was caused by the arrival of Homo sapiens into Europe, whether through indirect competition for food and resources, or direct violent clashes between the two groups. There is also recent genetic evidence that Neandertals and Homo sapiens interbred.
Now, new analyses of several fossils estimate that modern humans arrived in Europe much earlier, some 45,000 years ago. Meaning that Homo sapiens and Neandertals may have lived together in Europe for almost 15,000 years, according to two studies published this week in Nature.
The first study looked at the teeth of an infant found in Italy in 1964. Previously these teeth were believed to belong to an infant Neandertal. They were dated at 43,000 to 45,000 years old. However with new imaging techniques researchers say the teeth are closer to Homo sapiens' teeth than Neandertals'.
It is also significant that around these teeth, paleoanthropologists found intricate tools and beads. While Neandertals did make tools, their tools were generally fairly simple and show little diversity, according to AAAS member Ian Tattersall, a paleoanthropologist and curator emeritus at the American Museum of Natural History in New York City.
Researchers have debated whether Neandertals made more intricate tools and beads, and the fact that these tools were found with what are now thought to be Homo sapiens remains seems to suggest that they did not. Instead these tools were made by early Homo sapiens, further proving our greater tool use and more symbolic minds. The tools found near the Italian teeth belong to the Uluzzian culture, a culture believed to be Neandertal but now researchers may need to reevaluate that assumption.
A second group of researchers also relooked at some previously found fossils that now also suggest Homo sapiens entered Europe earlier than previously thought. A jawbone with three teeth was found in Kents Cavern in England in 1989. This jaw was originally dated at around 35,000 years old, the time we used to think Homo sapiens entered Europe. But using new techniques, researchers now date the jawbone at about 41,500 to 44,200 years old, the earliest Homo sapiens fossils in northwestern Europe. This dating is tricky because most of the radioactive carbon used for dating had decayed by around 30,000 years, so researchers relied on animal remains in the same cave. While this method has been successfully used in several other sites, the fact that the fossils themselves were not directly dated increases some people's skepticism.
Previously fossils were found in Romania dated at about 37,800 to 42,000 years old, the oldest in Europe. And no tools had been found near these fossils. But these new dating techniques suggest Homo sapiens entered Europe long before that, and coexisted with Neandertals for far longer than previously thought. While the dating on neither of the fossils is 100 percent certain, it certainly suggests we may have been living in much of the globe much earlier than previously thought. These developments further add to the mysteries we have about early Homo sapiens, their relationship with Neandertals and why only Homo sapiens survive today.
- Neanderthals were able to 'develop their own tools' (BBC, September 2010)
- Modern Humans' First European Tour (ScienceNow, November 2011)
- Fossil Teeth Put Humans in Europe Earlier Than Thought (New York Times, November 2011)
Want to learn more about the path of human evolution? This video with AAAS Fellow Ian Tattersall at the Hall of Human Origins at the American Museum of Natural History lays out how we now think Homo sapiens evolved from chimpanzees.