Hippos recognize each other's voices, respond differently to calls of strangers

[Still Waters]

Hippopotamuses are rather vocal animals. Their "wheeze honk" calls can be heard over long distances, leading researchers to suspect the calls play an important role in maintaining social groups. Now, a study in the journal Current Biology on January 24 shows that hippos recognize each other's voices. They also respond less aggressively to the calls of a neighbor compared to those of a stranger.

"We found that the vocalizations of a stranger individual induced a stronger behavioral response than those produced by individuals from either the same or a neighboring group," says Nicolas Mathevon of University of Saint-Etienne, France. "In addition to showing that hippos are able to identify conspecifics based on vocal signatures, our study highlights that hippo groups are territorial entities that behave less aggressively toward their neighbors than toward strangers."

https://phys.org/news/2022-01-hippos-voices-differently-strangers.html

https://www.cell.com/current-biology/fulltext/S0960-9822(21)01693-6