What can a small monkey cracking nuts with a stone tell us about the origins of tool use , and why is there still no theory to explain it? Primatologist Dorothy Fragaszy describes how wild capuchin monkeys develop remarkably skilled percussive tool use through years of socially supported exploration, challenging assumptions about what cognition tool use requires. Subscribe for more from the Convergent Science Network podcast series. Dorothy Fragaszy joins Paul Verschure and Tony Prescott at the BCBT summer school to discuss her fieldwork on tool use in wild bearded capuchin monkeys. These small primates, weighing only two to four kilos, routinely lift stones half their body weight to crack extremely resistant palm nuts with precision and control that takes years to develop. Fragaszy explains that tool use in non-human primates is rare , only a ha ...