A new study has concluded that Neanderthals could have been the world’s first freedivers.

Using a microscope, archaeologists recently looked at seashells discovered in a cave on the Italian coast in the late 1940s and determined that some of those shells came from below the surface of the water.

Scientists reckon that 100,000 years ago, the Neanderthals could have dived as deep as 13 feet (3.96 meters) to retrieve clams.

As University of Colorado archaeologist Paola Villa told The New York Times:

“Essentially, what they had to do was hold their breath and put their head underwater to see where to scoop with their hands in the sand to get the clam.”

The scientists’ findings were published last week in the Plos One journal:

“We prove that the exploitation of submerged aquatic resources and the collection of pumices common in the Upper Paleolithic were part of Neandertal behavior well before the arrival of modern humans in Western Europe.”

(Image credit: Plos One Journal)