Researchers from the University of Vienna analyzed Asian elephant sounds using an acoustic camera that visualizes sound pressure.
The elephants generated their low frequency "rumbles" primarily through their trunk or simultaneously through their mouth and trunk, and only rarely through their mouth alone.
This is the first study to show that combined oral and nasal call emission occurs in non-human animals.
The findings were just published in the journal "Animals."
Nasal pronunciation of elephants
Mylon Ollila/Unsplash
Elephants have the world's longest nasal elongation. Not unexpectedly, when released through the lengthy trunk, their low-frequency, partially infrasonic rumbles resonate much deeper, as per ScienceDaily.
Veronika Beeck and Angela Stoeger of the University of Vienna have recently demonstrated that these vocal tract resonances, often known as nasal pronunciation in human language, play an important role in animal communication.
The researchers believed that Asian elephants' higher vocal flexibility permits them to encode more information.
Furthermore, lower frequency resonances may improve call transmission over long distances.
Humans shape the resonances of their vocal tract by positioning their tongue, lips, and mouth aperture.
Humans "nasalize" the sound of vowels by opening the velum and allowing air to flow concurrently through the oral and nasal cavities.
In several languages, such as French or Hindi, nasalization of vowels affects the meaning of a word, such as beau [bo] in French meaning "beautiful" and bon [b] in Hindi meaning "good."
Mammals were formerly thought to have significantly less flexibility in modifying their vocal tract (the oral and nasal channels above the larynx) and thus the timbre of their cries.
Calls between animals frequently differ only by whether they are emitted through the mouth or nose.
The Viennese researchers collaborated with engineers Gunnar Heilmann and Michael Kerscher on this recent investigation.
They worked together to study the cries of Asian elephants in Nepal using an acoustic camera. Like a thermal camera, the acoustic camera displays sound pressure in color coding.
Most calls were made through the trunk. Surprisingly, the acoustic camera clearly showed calls emitted simultaneously through the lips and nose.
Veronika Beeck explained that the resonance spectra of these calls were remarkably close to those found in human nasal vowels.
Although this has previously been indicated in fallow deer, elephant seals, and Diana monkeys, this is the first study to establish orally and nasally coupled cries.
African elephants make a wide variety of noises, ranging from low-frequency Rumbles to high-frequency snorts, barks, roars, cries, and other distinctive sounds, as per Elephant Voices.
The very low-frequency Rumble is the most commonly used sort of call.
The Elephant Ethogram: A Library of African Elephants allows you to search for, listen to, and read about countless elephant cries and other sounds.
Many of The Elephant Ethogram's over 2,300 annotated video segments depict or feature vocal communication.
Sound is created when air released from the lungs passes across the vocal cords or larynx, a 7.5 cm long organ in elephants.
Depending on the type of sound the elephant makes, the moving air causes the vocal cords to vibrate at a specific frequency.
An elephant can create a wide range of frequencies by stretching or shortening its vocal cords.
The long vocal tract or resonating chamber of the elephant vibrates, and depending on how the elephant holds the various components of this chamber (trunk, mouth, tongue, pharyngeal pouch, larynx), it can modify and enhance different components of the sound.
Elephants can create very low-frequency sounds for a variety of reasons.
First, because they are large-bodied, they may make low-frequency noises; similarly to musical instruments, the longer and looser the vibrating string (or vocal cords) and the larger the resonating chamber, the lower the frequency produced.
Elephants, in addition to being large-bodied creatures, have many adaptations that allow them to expand their resonating chamber and lengthen their vocal cords.
One of these is the elephant's nasal cavity and trunk, which can add up to 2 meters to the length of the resonating chamber in an adult male.
