The sound of an elephant 'blowing its trumpet' is a familiar one. However, scientists have also worked out that elephants also use very low pitch sounds, too quiet for humans to hear, to communicate with one another.
For many years scientists have reasoned that elephants communicate through super-low sounds (or infrasonic sounds ranging between 1 and 20 hertz). Much of thinking was that the sound is produced by the elephant purring (much like a cat). This no longer appears to be the case.
Time reports that scientists based at the University of Vienna now believe that elephants 'sing' in low pitch sounds. This was based on measurements made by blowing air through the voice box of a recently deceased elephant at the Berlin zoo. What happened when the air was blown through was that as the air passed out of the lungs, strips of tissue in the voice box (larynx) of the elephant separated out and then connected again. This action created puffs that set the whole voice mechanism into action.
Humans also have folds of skin in their voice box which serve a similar function, Planet Save notes. The difference with elephants is that the elephant folds are eight times larger. The size difference noted, the findings indicate that primates and elephants communicate in a very similar way through muscular contractions.
This has led to the thinking that elephants exhale air through their vocal tracts in order to make sounds, a variety of which represent different things that an elephant wishes to communicate, such as signalling to the herd that it is time to move on.
The Times of India reports that using infrasonic sounds, scientists believe that elephants can communicate over distances of up to 10 kilometers (6 miles).
The research was led by Christian Herbst, Department of Cognitive Biology laboratory, and the findings have been published in the journal Science in a paper titled "How Low Can You Go? Physical Production Mechanism of Elephant Infrasonic Vocalizations".
The research, into low sound signal communication, might explain why elephants have such large ears.