A series of lines scratched into rock in a cave near the southwestern tip of Europe could indicate that Neanderthals were more intelligent and creative than previously thought.

The cross-hatched engravings inside Gorham's Cave in Gibraltar are the first known examples of Neanderthal rock art, according to a team of scientists who studied the site. The find is significant because it indicates that modern humans and their extinct cousins shared the capacity for abstract expression.

The study, released Monday by the journal Proceedings of the National Academy of Sciences, examined grooves in a rock that had been covered with sediment.