Male crested black macaque at an old camp fire, Tangkoko, Sulawesi.
In Tangkoko, Sulawesi, I was following a troop of black crested macaques when I became intrigued by a male who had separated from the main group. I followed him as he walked across the black sandy beach towards an old fire pit. He dug around inquisitively, moving the burnt out pieces of wood as if he was building a fire. Much to my surprise he then he started to chew on the charcoal. He may have been using this as a form of self medication to help relieve indigestion, a behaviour documented in colobus monkeys.