Hippo talk: study sheds light on purpose of call and response

Hippopotamuses recognise the voices of their pod-mates and members of nearby pods, and respond more territorially to strangers, according to a study in Mozambique. Scientists recorded and broadcast hippo “wheeze honks”, which sound like deep, resonant grunts. Animals were more likely to respond aggressively by spraying larger amounts of dung when they heard strangers. This suggests that if a hippo needs to be relocated for conservation reasons, it might help to make the local hippos a sort of ‘mix tape’ of the new hippo’s voice for them to listen to in advance, and vice versa.