Elephants Don't Just Trumpet—They Also Squeak

Ask a child what noise an elephant makes and they’ll no doubt lift an arm like a trunk and make a trumpeting sound. But it’s not the only sound these massive animals make. They also squeak.

Researchers have found that Asian elephants actually press their lips together and buzz them like humans playing brass instruments in order to make those high-pitched squeaking noises.

Their findings are published in the journal BMC Biology.

“Asian elephants had been described squeaking before, but it was not known and mysterious to us how they can do it, given their large body size and the very high pitch of the squeaks,” study author Veronika Beeck, a Ph.D. candidate in the department of cognitive biology at the University of Vienna, tells Treehugger.

Most research into elephant communication has focused on low-frequency rumbles, which are typically produced by the elephant’s very large vocal folds. Large vocal folds usually result in low frequency sounds, so it was unlikely that these mouse-like squeaks were made the same way, Beeck says.

There’s also an Asian elephant named Koshik in a Korean zoo that mimicked some words from his human trainer.

“To do so, he put his own trunk tip into his mouth, showing just how flexible Asian elephants can be in producing sounds,” Beeck says. “Still, since how they produce their unique squeak sound was unknown, we wondered what the function of this extreme vocal flexibility was when the elephants communicate with each other in natural conditions.”

Visualizing Sound

That iconic elephant trumpeting noise is made by forcefully blasting air through the trunk. Although it is familiar, the source of the sound and how it is produced is not well-studied or understood, says Beeck.

Elephants also roar, which sounds a lot like a lion’s trademark loud, long, harsh cry that they make when they are excited. Some elephants also snort and most elephants also rumble as ways to communicate.

But Beeck and her colleagues were fascinated with squeaking.

“We were particularly interested in the squeak sounds because they are unique to Asian elephants and so little was known about them, except that they are produced when Asian elephants are excited,” she says.

In order to visually and acoustically record elephants making noises, researchers used an acoustic camera with a star-shaped array of 48 microphones arranged around it. The camera visualizes sound in colors while recording it. They placed it in front of the elephant and patiently waited.

“Just like we hear where a sound comes from because the sound arrives at our left and right ears at different times, the different times the sound reaches the many microphones is used to exactly calculate the sound source,” Beeck explains. 

“Then, the sound pressure level is color-coded and put onto the camera image, just like temperatures are color-coded in a thermal camera and you can see where it is hot, here you see ‘loud.’ In that way, the sound source, and hence where the elephant emits the sound, can be visualized.”

Elephants were recorded in Nepal, Thailand, Switzerland, and Germany. There were 8 to 14 elephants in each group.

Learning to Squeak

With the help of the acoustic camera, the researchers could see three female Asian elephants make the squeaking noise by pressing air through their tensed lips. It was similar to the way musicians buzz their lips to play a trumpet or a trombone. Apart from people, this technique isn’t known in any other species.

“Most mammals produce sounds using the vocal folds. To overcome the limitations of vocal fold sound production and achieve higher (or lower) frequencies, some exceptional species have developed different alternative sound production mechanisms,” Beeck says.

Dolphins, for example, have what is known as phonic lips that allow them to produce high-pitched whistle-like noises. Bats have thin membranes on their vocal folds that allow them to whistle.

While elephants might be born with the ability to trumpet, they might have to learn to squeak.

Only about one-third of the elephants the researchers studied made any squeaking noises. But whenever the offspring were living with their mothers, they were both able to make squeaks which indicates that the elephant might learn how to squeak from a mom or close relation.

The findings are key for researchers studying what elephants learn from their family members and are important for animal welfare in captivity when considering keeping elephants together.

“Asian elephants may also lose adaptations or ‘knowledge’ that is passed from generation to generation where Asian elephant populations are in a steep decline everywhere in the wild,” Beeck says.

But the mechanics of making sounds is also fascinating to researchers

“It is still puzzling how we humans evolved our capacity to be so flexible when it comes to producing and learning sounds, which allows us to have languages and play music! So from a scientific point of view, it is very interesting to compare vocal flexibility in other species,” Beeck says.

“Only very few mammals have been found capable of learning novel sounds, cetaceans, bats , pinnipeds, elephants, and humans. Our closest living relatives, the non-human primates, have been found to be much less flexible in learning sounds. What common factors may have led to the commonalities and differences in cognition and communication across species?”