Madhur Mangalam, a graduate student in the Franklin College of Arts and Science’s Behavior and Brain Sciences Doctoral Program, was quoted by the Daily Mail in an article about a study that found monkeys adjust the force of stone “hammers” as they strike nuts to open them.
“Until now, this level of dexterity was not suspected of any monkey,” Mangalam said.
For the study, which Mangalam was a part of, researchers filmed 14 capuchin monkeys as they tried to open nuts in Brazil. The researchers then looked at the footage to determine the height and speed of each blow of the stone hammers. The study found that the first blow has a certain amount of force to crack the nut’s husk. After that, the monkeys can hit the inner shell of the nut harder.
“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 told the publication.