Neanderthals used plant fibers to create string more than 40,000 years ago at a site in France where they hunted reindeer, further evidence according to scientists of the ingenuity and cognitive capabilities of our closest extinct human relatives.

Researchers on Thursday described a string fragment — comprised of three small bundles of fibers twisted together into a cord — associated with a stone cutting tool that may have been used to skin animal carcasses.

The string dates to an occupation by Neanderthals at the Abri du Maras archeological site in southeastern France, 30 miles (50 kilometers) north of Avignon, between 42,000 and 52,000 years ago, where they apparently hunted reindeer during seasonal migrations.