Time for something a little different! This month, I am featuring the Serra da Capivara National Park, in the northeast of Brazil, over five weekend posts. This UNESCO World Heritage Site is of great interest to geologists, anthropologists, and animal behaviour scientists. It houses some of the oldest cave paintings in South America, and, for the animal enthusiasts among us, a tool-using population of capuchin monkeys. In this first blog post, I share some of the fauna inhabiting the park, including these clever primates. I was even lucky enough to watch them crack nuts with rocks for several minutes, and caught a couple of images of this behaviour too.