Home Environment To Hippos, a Wheeze and a Honk Mean More Than Just ‘Hello!’ [Video]

To Hippos, a Wheeze and a Honk Mean More Than Just ‘Hello!’ [Video]

by WDC News 6 Staff


Hippopotamuses are among the most unfriendly creatures within the animal kingdom.

“Aside from mosquitoes, they’re essentially the most harmful animal in Africa, those that kill the most individuals,” stated Nicolas Mathevon, a professor of animal habits on the College of Saint-Etienne in France. “Folks underestimate them. They swim very quick and don’t hesitate to assault boats. They’re within the water more often than not, however they’ll transfer out of the water very quick. Getting into their territory could be fairly harmful.”

However you’ll be able to’t say that hippos don’t give satisfactory warnings to strangers.

The massive mammals make loud noises, and Dr. Mathevon and his colleagues have labored out a few of what they imply. Their outcomes, published Monday in Current Biology, counsel that hippopotamuses can distinguish pals from acquaintances, and acquaintances from strangers, by the way in which they sound.

Hippos are arduous to review. It’s nearly unimaginable to establish and mark particular person animals, and troublesome to seek out them even when marked. They spend the night time feeding on land, after which retreat to the water through the day, gathering in teams with a dominant male guarding quite a lot of females and younger animals. People might transfer from one pod to a different — the small print of their social group are poorly understood.

However Dr. Mathevon and colleagues endured. They studied the animals on the Maputo Particular Reserve in Mozambique, the place a number of lakes are inhabited by a number of teams, or pods, of hippos. There, the researchers recorded the calls of hippos in seven pods.

The researchers made their recordings cautiously, from not less than 250 ft away, utilizing subtle video gear and a shotgun microphone designed to select up distant sounds. Then they performed recordings again to the others whereas videotaping their responses.

They discovered that hippos make a whole lot of noise. Their “wheeze honks” could be heard greater than a half-mile away, and their verbal repertoire contains grunts, bellows and squeals. The wheeze honk is mostly thought of the way in which hippos announce their presence, however its social perform is unclear.

In 10 separate experiments, the scientists performed recorded calls to the animals utilizing three exams: first by enjoying a hippo’s voice to its personal group, second utilizing a name from a neighboring group in the identical lake and eventually with the sound of a stranger from one other lake. They made movies of all of the responses.

Hippos reply to calls by calling again, approaching the caller or marking their territory by defecating whereas flicking their tails to unfold the feces. The animals responded not directly to recorded calls from any group, however the depth of the response was lowest once they heard recordings of people from their very own pod and highest once they heard the honk of a distant stranger. The response to a name from a neighboring group was little totally different from that of 1 from the identical group, and solely listening to the decision of an animal from a pod of strangers provoked territorial marking.

In animal habits research, it may be troublesome to keep up objectivity, Dr. Mathevon stated. “There’s at all times a hazard to think about issues that don’t exist,” he stated. “So it’s a must to take some precautions,” in each the methods for gathering information and the strategies used to interpret it.

Earlier than every recording, the researchers waited till the animals have been calm and quiet. 5 totally different observers made assessments of the variety of hippos, and in contrast their counts. Researchers not concerned in producing the movies scored the responses of the animals on three-point scales utilizing three standards: distance of strategy towards the sound, diploma of marking by dung spraying and variety of hippos vocalizing.

The research might have implications for the preservation of the species. Hippopotamus populations are declining, and the Worldwide Union for Conservation of Nature classifies them as weak.

“The discovering that hippos present stronger behavioral reactions to the calls of an unknown hippo could be utilized to conservation efforts,” stated Diana Reiss, an animal habits researcher and professor of psychology at Hunter School in New York who was not concerned within the research. “It might be essential and helpful to habituate hippos that will have to be relocated to different areas for conservation functions, to the calls of unfamiliar hippos they are going to be encountering in new areas.”

The research highlights that there’s a lot to study hippo habits and group dynamics.

“Hippos have a social system that’s sophisticated, with numerous interactions,” Dr. Mathevon stated. “That normally goes together with complexity within the vocal system. We present that hippos can distinguish acquainted and unfamiliar voices. However our research is simply a primary step.”



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