Stone tools in Portugal cave indicate humans and Neanderthals may have inhabited the same region at the same time

The discovery of stone tools in a cave near the Altlantic coast of Portugal may indicate humans reached westernmost Europe between 38,000 and 41,000 years ago, approximately 5,000 years sooner than previously thought and in a time when Neanderthals still lived there.

Jonathan Haws of the University of Louisville and an international team of researchers recently published a report in Proceedings of the National Academy of Sciences about their discovery, which links the site to similar finds across Eurasia to the Russian plain, according to a post on the National Science Foundation website. The tools place modern humans in the region during a time scientists believe Neanderthals still lived there.

Project co-leader Lukas Friedl said the early dating of stone tools associated with modern humans would "likely rule out the possibility that modern humans arrived into the land long devoid of Neanderthals, and that by itself is exciting," according to the post.

In addition, the cave still has not been fully explored, and may yet yield more clues regarding its past inhabitants, according to the post.