Elephants have a private means of communicating that, though loud as a chainsaw and able to travel for miles, is impossible for human ears to hear.
The phenomenon is known as infrasound, which is essentially the opposite of ultrasonic noises, which are too high for human ears to perceive. Whereas animals such as bats emit ultrasonic sounds, elephants’ giant organs send out infrasound signals, enabling them to communicate across large distances in the forest.
“These low-frequency sounds, termed ‘infrasounds,’ can travel several kilometers and provide elephants with a ‘private’ communication channel that plays an important role in elephants’ complex social life,” explained the authors of the paper that originally discovered this phenomenon in a statement. “Their frequencies are as low as the lowest notes of a pipe organ.”
Scientists have known about this occurrence for years but weren’t sure how the elephants could emit such low frequencies. To gain further insights, a team of researchers removed the larynx of an elephant that died of natural causes and blew a controlled stream of air through it under lab conditions.
The team could recreate the low-frequency vibrations that characterize infrasounds by manipulating the vocal folds. This means that when the elephants communicate using infrasound, they’re effectively singling, but with an immense larynx that can reach notes far below a human baritone.
The new research disproved a previously held theory suggesting low-frequency sounds were more like a purring. This discovery also demonstrates that humans connect with elephants in the mechanism through which we create sound.
This discovery could also have implications for future studies of whales, which emit sounds at frequencies even lower than those of elephants.
