We’re in the number one spot, given all of our gadgets and machinery that can crack nuts, but the monkeys appear to be a close second, since they have their own tools and techniques for getting at the nutritious, tasty snack. (Chimpanzees could tie for second or be a close third, since they too are clever at this.)
A study in the journal Current Biology describes how the monkeys place uncracked nuts on an anvil, which is usually a piece of hardwood with a depression in it. Using a large rock, the monkeys then smash down on the nut. Next, they examine the nut, to see where the most vulnerable crack is, and then strategically hit that spot, which usually reveals the nutmeat.
“Wild bearded capuchin monkeys dynamically modulate their strikes based on the outcome of the preceding strike while using stone hammers to crack nuts,” co-author Madhur Mangalam of the University of Georgia at Athens said in a press release. “Until now, this level of dexterity was not suspected of any monkey.”
It’s long been known that the monkeys were good nut crackers that used tools, but the process seemed to be trial and error.
Mangalam, lead author Dorothy Fragaszy and their team took a closer look by videotaping 14 capuchin monkeys cracking nuts. Analysis of the height and velocity of each and every strike found that the smashing was not random at all.
“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.