Neanderthals, once considered the low-brows of human evolution, may have been among the world’s first artists, creating cave paintings long before modern humanity arrived on the scene, scientists reported in two new studies Thursday.

Although these primitive cousins of humankind mastered fire and made tools, most archaeologists have assumed until now that they lacked the cognitive capacity for artistic expression, unlike early humans who painted vivid images of lions, rhinos and other animals on cave walls.

In the new studies of paintings in three Spanish caves, archaeologists used a sensitive dating technique to measure minerals that had slowly built up as water dripped onto the paintings over time. It revealed that these prehistoric images had been painted at least 64,000 years ago—a time when Neanderthals were the only hominids inhabiting Western Europe, the scientists said.

“We conclude that this cave art has to be made by Neanderthals,” said physicist Dirk Hoffmann at the Max Planck Institute for Evolutionary Anthropology in Leipzig, who led researchers from 15 centers in Germany, the U.K., Portugal and Spain. They published their findings in the journals Science and Science Advances.

The researchers studied caves at La Pasiega in northeastern Spain, Maltravieso in western Spain and Ardales in southwestern Spain.