Neanderthals were artists, according to a new study in Science, which reveals that the oldest cave art found in Europe predates early modern humans by at least 20,000 years, and so must have had Neanderthal origin. The findings mark the first clear evidence that our extinct cousins created cave drawings. In a related study in Science Advances, researchers also studying caves in Spain report that dyed and decorated marine shells - items of assigned value that serve as proxies for the presence of language - also date back to times before the known appearance of modern humans in the region. Together, the reports suggest that Neanderthals exhibited complex symbolic communication systems, the emergence of which, for our species, has been hard to pinpoint because of difficulties in precise and accurate dating. In the Science study, Dirk Hoffmann and colleagues explain that several instances of cave art have been suggested to have been created at the hands of Neandertals; however, the dating of these artworks, and whether they were intentional, remains controversial. Here, using a new dating technique, the authors analyzed isotope samples from three Spanish caves - La Pasiega, Maltravieso, and Ardales. The caves contain red and black paintings of animals, linear signs, claviform signs, and dots, as well as stencils of hands (whereas a full handprint could be accidental, say the authors, stenciling a hand is a clearly intentional art). They used a dating technique that involves analyzing carbonates both above and below the surface of the cave art, in order to narrow the window of minimum and maximum possible dates for its creation. The minimum ages from the three collections of cave art were consistently dated to be approximately 64,800 years in age or older. Fossil evidence suggests that Neanderthals were the only hominin species in Europe at such points, pointing to Neanderthals as the artists, the authors say. Modern humans are estimated to have arrived in Europe much later, between 45,000 and 40,000 years ago. At Ardales, the authors report that the dates of various paintings spanned a period of 25,000 years, suggesting that the creation of art was not a one-off burst, but a long tradition. In the Science Advances study, involving a different Spanish cave, Hoffmann and colleagues describe punctured and colored marine shells which they also date to significantly earlier than the estimated arrival of early modern humans in Europe. The use of such artefacts is associated with the emergence of symbolic materialism, which represents a critical moment in the evolution of our species. However, to date, the earliest symbolic artefacts uncovered by scientists are estimated to be about 92,000 years old, were found in Africa and are thought to be created by early modern humans. At Cueva de los Aviones, Hoffmann et al. used sedimentary and isotope data to determine the age of the marine shells and shell containers that are stained with red and yellow pigments. They found that two of the four samples analyzed date to roughly 115,000 years old - again, much farther back in time than the known presence of early modern humans in the region. The authors say that these findings - both the cave art and decorated artifacts - leave "no doubt that Neanderthals shared symbolic thinking with early modern humans." Therefore, they propose that the capacity for symbolism may have been inherited from the common ancestor, and did not acquire it from modern humans as they entered Europe.