When it comes to cracking nuts, capuchins don't monkey around.
Just have a look at this video showing a little monkey named Jatobá expertly crack a tucum nut. Five quick whacks, and voila!
The video was taken as part of a new study on wild-bearded capuchins (Cebus libidinosus) living in the open woodland of Piaui, Brazil.
"Until now, this level of dexterity was not suspected of any monkey," Madhur Mangalam, a psychology graduate student at the University of Georgia at Athens and one of the researchers involved in the study, said in a written statement.
For the study, Mangalam and her colleagues recorded 14 capuchins cracking nuts with a stone "hammer," and then analyzed the videos to determine the force of each strike. To their surprise, the scientists found that the monkeys don't simply whack a nut over and over until it breaks open. Instead, they monkeys examine the nut after each strike and artfully adjust the amount of force they use -- so as to save their energy and prevent the nut's kernel from getting smashed.
"It was a 'eureka' moment when we realized that the monkeys modulated the strikes systematically according to the condition of the nut following the preceding strike," Mangalam said in the statement.
A paper describing the research was published on April 29 in the journal Current Biology.