The studies carried out in ethology made it possible to understand the mode of communication between animals of the same species. Recently, ethologists discovered that the social communication in hippos is done by speech Recognition. The latter also mentioned that this mode of identification allows them to manage reports within the different territorial groups.
During their study, these scientists found that the voice emitted by an unknown animal induced a strong behavioral reaction in hippos. This reaction is less strong when it comes to the animals of a neighboring group. For them, the hippos were able to recognize their congeners from their voices.
Furthermore, they pointed out that hippopotamuses adopt a behavior less aggressive towards their congeners than towards strangers. The results of this study were published in the magazine Current Biology.
From typical howls to each clan of hippos
Dr. Mathevon and his team carried out their study while working in Maputo, capital of Mozambique, in a special reserve. This area is made up of a few lakes occupied by hippos.
First, the researchers recorded typical howls to each clan of hippos. Then the recordings were broadcast to other hippopotamus clans to determine their reactions facing the howls of their peers. They compared these reactions to those observed when dealing with a neighboring clan or a foreign group.
Sharper sound reactions to strangers
After taking the steps, the ethologists realized that these mammals react to a cry with a voice responsea approach and/or a feces throw. Interestingly, this answer changes depending on whether they heard their congeners or strangers. Additionally, the hippos’ reaction increased when they heard a stranger.
Furthermore, these megaherbivores were more likely to spill their excrement upon hearing the cry of a hippopotamus unrelated to their circle. It’s a way for them to mark their territory.
” When in the water, hippos seem inactive. However, the results of this survey indicate that these animals are really very attentive to their environment. As soon as they perceived the call of another hippopotamus coming from the bank, they immediately reacted. Responsiveness to audio calls that played out was really crisp, something we didn’t expect. [..] This study will determine the means by which they distinguish the calls of another hippo and whether the voices give away information such as sex, size or age. »
Doctor Nicolas Mathevon, collaborator and researcher at ENES/CRNL, Institut Universitaire de France and University of Saint-Etienne.