I was following a group of black macaques in Tangkoko, Sulawesi. This male broke away from the rest of the group and went to investigate an old fire pit. He dug around and pulled out a lump of charcoal which he started to chew. This behaviour has been documented as a in other species as a form of self medication to help neutralise plant toxins. To me this shot captures the inquisitive nature of these criticically endangered monkeys.
Canon 7D, ISO 100, 14mm, f7.1, 1/250