Researchers have been studying hippos in Mozambique and found that they can distinguish other hippos by their vocalisations, particularly whether they’re friend or foe:
“Hippos are quite talkative. They have a repertoire of different calls: wheeze honks, grunts, bellows, squeals,” said Prof Nicolas Mathevon, of the University of Saint-Etienne in France, a co-author of the study. “However, the function of these calls has not been studied experimentally. Our study is the first to test experimentally the function of a hippo call.”
But the team offered words of caution when relocating hippos for the sake of conservation:
[…] While relocating endangered animals to maintain populations above critical levels is increasingly common10, our results suggest that precautions should be taken during such relocations with hippos. Before transferring a group of hippos to a new location, a potential precaution could be to broadcast their voices from a loudspeaker at a distance from the groups already present so that they get used to them and their level of aggressiveness gradually decreases. Getting the animals to be relocated accustomed to the voices of their new neighbors could also be considered.
Basically, French exits for hippos are bad. They have to let their friends know they’re leaving and let the new hippos know they’ve arrived.
More on hippos: Pablo Escobar’s hippos in Colombia living their best lives and Tam Tam: the cutest baby pygmy hippo in Japan