When it\'s time for elephants at an African watering hole to leave, the matriarch initiates a coordinated \"conversation\" with herd leaders, researchers say. The matriarch kicks off the conversation with what scientists have dubbed a \"let\'s-go rumble\" while steadily flapping her ears, setting off a series of back and forth vocalizations, or rumbles, within the group before the entire family finally departs, Stanford University researchers report in the journal Bioacoustics. This measured and documented behavior shows elephants are a cognitively advanced species capable of using well-coordinated \"conversations\" to initiate cooperation within the group, lead author Caitlin O\'Connell-Rodwell said. \"These vocalizations facilitate the bonds between the elephants to be able to work together,\" she said. \"It\'s the measure of an organized society. It demonstrates how another social animal grouping organizes itself through vocalizations.\" The study confirmed elephants use vocalization to coordinate action, and that usually three callers are involved in this very coordinated turn-taking conversation. \"It\'s not just a chorus,\" O\'Connell-Rodwell said. \"As soon as one call ends, another call starts, then the next, then the next. It\'s connected like a string. Effectively they take a 3-second call and turn it into a 9-second call.\"