New Scientist

Image: Dick Knight

They are literally a tough nut to crack. To enjoy tasty cashews you first have to figure out a way to remove the shells, which contain a caustic chemical.

The bearded capuchin monkeys of Brazil may have been up to the task for centuries – and watching them work could even have taught us how to eat cashew nuts safely.

We know that at least three non-human primates use stone tools: chimpanzees in West Africa, long-tailed macaques in Thailand and bearded capuchins in Brazil. The first ever “primate archaeology” dig – carried out in Ivory Coast and published in 2007 – confirmed that chimpanzees have been living through their Stone Age for at least 4300 years. A similar investigation in Thailand published earlier this year traced back the macaque Stone Age at least 65 years.

Now, Michael Haslam at the University of Oxford and his colleagues have done the same feat in the Americas, by finding ancient evidence of the capuchin Stone Age. Read more on newscientist.com…