Lines etched into the wall of Gorham's Cave on the British Mediterranean island of Gibraltar could be the first known examples of Neanderthal rock art. That's according to a study released on Monday by the journal Proceedings of the National Academy of Sciences.

The pattern of lines, dating back 40,000 years, was first spotted in July 2012 by director of Spain's Archaeological Museum of El Puerto Santa Maria, Francisco Giles Pacheco.

They bear a remarkable resemblance to the grid for the pencil-and-paper game of 'Noughts and Crosses' and even today's routinely used Twitter #hashtag.

The eight partially criss-crossing lines with three shorter lines on the right and two on the left, have been described as "a major contribution to the redefinition of our perception of Neanderthal culture."

This new evidence suggests that the intellectual abilities of Neanderthals may have been hugely underestimated. Neanderthals are named after the site of an 1856 discovery in the Neander valley, east of Düsseldorf in western Germany.

Abstract thought

Professor Clive Finlayson, director of the Gibraltar Museum and one of the study's authors, said the latest discovery "brings the Neanderthals closer to us, yet again" - ruling out previous portrayals of Neanderthals as brutes and incapable of abstract thought.

"This engraving represents a deliberate design conceived to be seen by its Neanderthal maker and, considering its size and location, by others in the cave as well," Finlayson and his colleagues wrote. "It follows that the ability for abstract thought was not exclusive" to modern humans.

Other recent finds have implied that our extinct cousins intentionally buried their dead, adorned themselves with feathers, painted their bodies with black and red pigments, and consumed a more varied diet than had previously been thought.

Persistence and determination

Researchers at the Gibraltar site have dismissed the possibility that the patterns were unintentional marks from cutting meat or animal skins.

In order to fully comprehend how the markings were made, experiments were carried out, creating grooves on blocks of dolomite rock, similar to the one at Gorham's cave, using different tools and cutting techniques.

The archaeologists instead claim that the lines were created using a sharp stone tool to etch into the rock, showing the personality traits persistence and determination. One line is thought to have required at least 54 strokes and the entire pattern as many as 317.

Found alongside the engravings were 294 stone tools in an undisturbed sediment dating back 39,000 years - about the time when Neanderthals became extinct - meaning the art below it must be older. The tools are in made in a long-known signature Neanderthal style, who reached Europe from Africa some 300,000 years ago.

Research in Germany

Further insights into the differences between modern human and Neanderthal cognitive abilities could soon come to light, thanks to a catalogue being compiled by Professor Svante Paabo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

This will record the genetic mutations in modern humans after the Neanderthals, including those involving in brain function.

Finlayson, however, remains confident of the marks' Neanderthal origins. "All European Neanderthal fossil sites from this period, including Devil's Tower Rock Shelter just one mile from Gorham's Cave, have this technology associated," said the anthropologist.

"In contrast no modern human site in Europe has this type of technology. So we are confident that the tools were made by Neanderthals."

ksb/jr (Reuters, AP, AFP)