Markings found by scientists deep in Gorham's Cave in Gibraltar that date back 40,000 years ago suggests Neanderthals were more sophisticated than previously thought.

The researchers came to their conclusion after finding the engravings, which are believed to be the first Neanderthal cave etchings found anywhere across the globe, according to AFP.

It also shows that Neanderthals possessed the capacity for abstract thought and expression.

"It brings Neanderthals even closer to us," said Professor Clive Finlayson, the director of the Gibraltar Museum and coordinator of the international team that carried out the research, according to AFP.

"It talks of high cognitive mental capacities in Neanderthals which are equivalent to humans."

Their findings were published recently in the journal Proceedings of the National Academy of Sciences of the United States of America.

The paper, titled "A rock engraving made by Neanderthals in Gibraltar," was authored by a team that included specialists in the Neanderthal field like Joaquin Rodriguez-Vidal, Francesco d'Errico and Francisco Giles Pacheco.

"The production of purposely made painted or engraved designs on cave walls is recognized as a major cognitive step in human evolution, considered exclusive to modern humans," the authors wrote in the paper.

D'Errico, of the French National Center for Scientific Research (CNRS), said it is "the first example of cave art, an abstract representation made by Neanderthals and deeply engraved in the rock in a part of the cave they lived in," according to AFP.

The carving was discovered after years of excavation at Gorham's Cave under a Neanderthal sediment level that was found below a modern human sediment level.

It was the first area of bedrock that was exposed by the researchers, meaning there could be other engravings they haven't found yet.

The researchers believe the engraving was made by using a stone tools.

"To produce one of the grooves required 60 strokes, always in one direction," Finlayson said, adding that the etching required up to 317 strokes. "We were immediately showing that this was not a casual mark. This required effort."

The cliff is located overlooking the Mediterranean Sea, where previous evidence suggests Neanderthals retired to rest.

"If there's going to be a place where you're going to have spare time to do these things, it's going to be there," Finlayson said.

Neanderthals lived in parts of Central Asia, Europe, and Middle East for up to 300,000 years but vanished around 35,000 years ago.

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