Humans aren’t the only animals that know how to wield a tool. Bearded capuchin monkeys, a species that lives in Central and South America, use stones to crack tucum nuts against logs and rocky outcroppings that act as natural anvils. The surprisingly dexterous primates can even adjust their tool use on the fly based on the way the nut is cracking, a new study in the journal Current Biology shows. 

Madhur Mangalam and Dorothy Fragaszy, psychologists from the University of Georgia, observed 14 capuchin monkeys in Brazil cracking open nuts, repeatedly slamming the nut against a log using a large stone. 

Image Credit: Carlos Carvalho

When the researchers analyzed these movements, they found the monkeys moderated the force of their strikes to minimize the risk of crushing the food and to save energy. The monkeys could also change their strikes based on the changing requirements of the task, similar to what a human might do with a hammer. They modulated the force with which they struck the nut based on whether or not the previous strike had created any cracks in the hard outer hull. 

By studying primates’ abilities to use tools, researches hope to illuminate the process behind the evolution of the more complex activity of knapping, the process of shaping stones into tools.

"Our finding opens our eyes to the fact that non-human primates modulate their actions with a tool to accommodate the rapidly changing requirements of the task, which is a cognitive accomplishment," Mangalam said in a press statement. That’s some monkey talent, right there. 

[h/t: Pacific Standard]