The University of Georgia filmed capuchin monkeys in Brazil and found that they expertly adjust the force of each strike according to the condition of the nut following the preceding strike.

Admittedly, this trick is unlikely to replace a nutcracker if you need to crack open many walnuts at a time, but it works in a pinch and is sure to impress your friends.

The crafty little monkeys of Boa Vista in Brazil are often seen using heavy rocks to crack open large palm nuts. Now, researchers say they are experts at choosing the best stones for the job.

I put the Brazil nuts, still in their shells, in the freezer. I take out a handful and crack the frozen nut. They often come out whole or in large pieces.

Cracking the case: New study sheds more light on the “Brazil nut effect” Shape and orientation of a given Brazil nut is the key to its upward movement.