washingtonpost.com – Wild bearded capuchin use stone stools to crack crashew nuts in Serra da Capivara National Park in northeast Brazil. (Michael Haslam/Primate Archaeology Project)

The sound can be heard from a distance. Bang, bang, bang! Clack, clack, clack!

Hairy little arms raise a stone, then bring it down with force on a cashew still in its sack of tough skin and toxic resin. The sound echoes as the stone smashes the nut on a bigger stone used as an anvil. A hungry capuchin monkey wants the meal contained inside.

A new study by scientists at the University of Oxford determined that monkeys have been opening cashews this way in Brazil for seven centuries — long before Christopher Columbus arrived in the Americas to claim it as the New World.