Specialized bone tools, made by Neanderthals, have been found by researchers, suggesting they were more advanced than previously thought, according to CBS News. The tools were made in Europe thousands of years ago, before modern humans are thought to have developed the necessary skills.

This discovery, which has been published by the Proceedings of the National Academy of Sciences, provides the first evidence that Neanderthals may have developed bone tool technology on their own.

The tools discovered consisted of four fragments of bone that were found in southwestern France, which researchers believe were used as lissoirs, or smoothers, which would make animal hides tougher and more water resistant.

The oldest tool is thought to be 51,000 years old. The other tools are between 42,000 and 47,000 years old.

Previously, archaeologists thought that modern humans had taught Neanderthals how to make tools, but this new evidence disputes that, as modern humans are only thought to have reached that area of Europe 42,000 years ago.

"It's adding to a growing body of research, that's growing quite rapidly at the moment, that's showing that Neanderthals are capable and did produce tools...in a way that is much more similar to modern humans than we thought even a couple of years ago," Rachel Wood, an archaeologist and researcher in radiocarbon dating at Australian National University.

It's possible that other Neanderthal dig sites contain similar tools, Shannon P. McPherron, one of the archaeologists who participated in the dig, said. It's also possible that other Neanderthal dig sites may contain similar tools.

"It's like looking at pencil leads," McPherron continued. "Once you sort of get the pattern, it's a lot easier to spot them."

There is also a possibility that the Neanderthals were the ones to teach modern humans how to make lissoirs, though modern humans started making specialized bone tools independently.

"Based on this find, to make statements about the transition or the interaction between Neanderthals and modern humans is really, well, you really have to stretch the evidence very far to get to this conclusion," Sabine Gaudzinski-Windheuser, a professor at Mainz University, said regarding the find.