Neanderthals, forerunners to modern humans, buried their dead, an international team of archaeologists has concluded after a 13-year study of remains discovered in southwestern France.

Their findings, which appear in the journal Proceedings of the National Academy of Sciences, confirm that burials took place in western Europe prior to the arrival of modern humans.

"This discovery not only confirms the existence of Neanderthal burials in Western Europe, but also reveals a relatively sophisticated cognitive capacity to produce them," explains William Rendu, the study's lead author and a researcher at the Center for International Research in the Humanities and Social Sciences (CIRHUS) in New York City.

CIRHUS is a collaborative arrangement between France's National Center for Scientific Research (CNRS) and New York University.

The findings center on Neanderthal remains first discovered in 1908 at La Chapelle-aux-Saints in southwestern France. The well-preserved bones led its early 20th-century excavators to posit that the site marked a burial ground created by a predecessor to early modern humans. However, their conclusions have sparked controversy in the scientific community ever since, with skeptics maintaining that the discovery had been misinterpreted and that the burial may not have been intentional.

Beginning in 1999, Rendu and his collaborators, including researchers from the PACEA laboratory of the University of Bordeaux and Archeosphere, a private research firm, began excavating seven other caves in the area.

In this excavation, which concluded in 2012, the scientists found more Neanderthal remains-two children and one adult-along with bones of bison and reindeer.

While they did not find tool marks or other evidence of digging where the initial skeleton was unearthed in 1908, geological analysis of the depression in which the remains were found suggests that it was not a natural feature of the cave floor.

As part of their analysis, the study's authors also re-examined the human remains found in 1908. In contrast to the reindeer and bison remains at the site, the Neanderthal remains contained few cracks, no weathering-related smoothing, and no signs of disturbance by animals.

"The relatively pristine nature of these 50,000-year-old remains implies that they were covered soon after death, strongly supporting our conclusion that Neanderthals in this part of Europe took steps to bury their dead," observes Rendu. "While we cannot know if this practice was part of a ritual or merely pragmatic, the discovery reduces the behavioral distance between them and us."