Hippos in Mozambique Release Poop Tornado to Unfamiliar Hippos: New Study

Hippos (Hippopotamus amphibius) are conventionally known to be territorial animals and produce a 'wheeze honk,' characterized as a high-pitched wheeze sound, when communicating with other hippos.

The initial wheeze is followed by several honks in a quick and loud phase, according to Maria Maust-Mohl, an associate professor in psychology at Manhattan College in New York City. It is through these sounds that hippos recognize a familiar from an unfamiliar hippo.

Scientists are not aware of other responsive behavior of hippos to both familiar and stranger hippos until a new study has been published in the journal Current Biology on Monday. The study shows researchers were able to observe hippos at the Maputo Special Reserve in Mozambique release a spray of dung, also called as a poop tornado, as a means to mark their territory from the calls of an unfamiliar hippo.

Unfamiliar hippos are classified as living either in the same territory, a nearby territory, or a far territorial area. The study also suggests hippos are less aggressive toward other hippos within their social group, whose members are familiar to them, compared to strangers.

Implications on Wildlife Relocation

The findings of the recent study could help relocating the animals with the objective of reducing aggression between different groups of hippos. Nicolas Mathevon, of the University of Saint-Etienne in France, suggested "before relocating a group of hippos to a new location, one precaution might be to broadcast their voices from a loudspeaker to the groups already present so that they become accustomed to them and their aggression gradually decreases."

Mathevon added this method will for reciprocity, which will allow hippos living in a particular territory to become familiarized with their new neighbors.

Further Studies Expected

In spite the breakthrough concerning the unusual hippo behavior, the study is still far from complete. The amount of data used by the researchers was raised as the sample size is relatively small, said Camille Fritsch, a postdoctoral researcher at the University of KwaZulu-Natal in South Africa.

The recent study sampled hippos from seven different groups, ranging between 3 and 22 hippos, living on the lakes at the Maputo Special Reserve. Fritsch has suggested further study must be repeated in larger groups of hippos under different habitats and time of the year, adding that the population of hippos are distributed between the rainy and dry season.

Fritsch assured that further studies will be conducted to determine unexplored areas relating to hippos. Researchers in future studies are expected to learn additional information on the meaning of hippo communication and whether this communication reveal their characteristics, including hippo age, sex, or size.

The recent study is just the onset on how we do not know much yet on how hippos communicate for both familiar and unfamiliar hippos. Thus, further studies surrounding hippo communication and responsive behavior are likely to continue in the coming years.