Nut-cracking monkeys don't just use tools. They use tools with skill.
That's the conclusion of a new study that finds similar tool-use strategies between humans and Brazil's bearded capuchin monkeys, which use rocks to smash nuts for snacks. Both monkeys and humans given the nut-smashing task take the time to place the nuts in their most stable position on a stone "anvil," the study found, keeping the tasty morsels from rolling away.
That means the monkeys are able to not only use tools, but to use them with finesse. This ability may be a precursor to humans' ability to adapt tools to different circumstances and to use them smoothly under varying conditions.
"Any one individual can accomodate stones of different sizes, anvils of different angles and material and nuts of different shapes and sizes," said study leader Dorothy Fragaszy, a primate researcher at the University of Georgia, adding, "In fact, some of these nuts people can't crack."
Nut-crackers Bearded capuchin monkeys were the first non-ape primates to be discovered using tools in the wild. They crack tough nuts by placing them on pitted stone anvils and then hitting them hard with other large rocks. (8 Humanlike Behaviors of Primates)