Elephant’s Code of Communication Cracked

Scientists believe they have a better grasp on how elephants are able to make the sounds that help them communicate to one another. As one of the most vocal animal species, elephants have acquired a vast collection of calls and signals to use for as many purposes. To announce an individual’s desires and needs, to converse between partners and families, to call for mates or potential mates, as warnings of danger, or to prepare for incoming threats—these are but a few of the reasons elephants rely greatly on their ability to communicate.

In the past, researchers have dived fully into the topic of elephant communication to try and “crack the code” behind the sounds. While looking into the topic, elephant researcher Joyce Poole found that elephants use more than 70 types of vocal sounds to express themselves to their clan. Add these are just the noises that we humans are able to hear. As it turns out, much of elephant communication is carried out on a sound frequency too low for humans to hear, between one and 20 Hertz per second. These incredibly low-pitched vocalizations are known as infrasounds and can travel for miles.

With this information already largely considered, a new set of studies went underway to try and discovery how these low-registering sounds were produced. Were the infasounds produced by a set of quick muscle contractions like that of a cat purring, or were the sounds coming from air being pushed through the vocal chords like that of a human voice? After the unfortunate but natural passing of an elephant at a Berlin zoo, researchers were granted the chance to study the vocal mechanism—the larynx—firsthand.

Christian Herbst of the University of Vienna, along with his colleagues, began their process by removing the elephant’s larynx and freezing it within hours of the animal’s passing. The organ was then taken to the larynx laboratory at the University of Vienna’s Department of Cognitive Biology, where Tecumseh Fitch joined the team and authored the project. It was this collaboration between voice scientists and biologists that set the research on the correct path.

In order to test the larynx out, Herbst and researchers began to mimic the animal’s lung by blowing humid air through the larynx. The vocal folds were adjusted to “vocal ready” positions and the infrasounds were successfully produced. Because the scientists were able to replicate these sounds almost effortlessly, this shows that elephants utilize a myoelastic-aerodynamic method of communication—or, in the same way as humans. From this, the team inferred that many animal sounds off the grid from human perception are caused in the same manner.

Additionally, another (nonlinear) phenomenon became even clearer. These “nonlinear phenomena” are present when it seems that a note on the human scale of hearing is hit—remember that screaming baby on an airplane? That one. Elephants, it turns out, are able to hit these notes as well. “If I scream, it’s no longer a periodic vibration. It becomes chaotic and you can hear a certain degree of roughness,” Herbst explained. “This can also be observed in young elephants, in situations of high excitement.”

 

Photo Credit: news.science360.gov/obj/pic-day/ef37d299-6d7c-4319-ab34-4e71114d36fe/elephant-family

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