Biologists have discovered how elephants produce infrasound, with which they communicate with each other — it turned out that they use the same mechanisms as the man for the speech, according to a paper published in zhurnaleScience.
Elephants can communicate over long distances with the help available to the human ear sounds very low frequency — less than 20 Hz. In some cases you may notice the sound, but he hears not their own, and more high frequency harmonics — sounds arising from the application of several sound waves.
Until now, scientists did not know how elephants produce these sounds. Some believed that their source — intermittent muscle vocal apparatus, such as those that produce cat when murchat. Others believed that infrasound appear as "normal" sounds — due to vibration of the vocal cords under the flow of air from the lungs.
Christian Herbst (Christian Herbst) from the University of Vienna and his colleagues were able to clarify this issue by the death of an African elephant in the Berlin Zoo. The scientists made the larynx of the deceased elephant part of the experimental setup. Passed through a cut throat air flow from artificial light. Receive audio MIC, and the position of the vocal cords was filming a high-speed video camera.
"We have shown that low frequency sounds may occur due to the flow of air, which creates a self-sustaining oscillation of the vocal cords … that eliminates the need for the existence of any" murchaschih "mechanisms (formation of sounds by reducing the muscle)," — says the article .
The authors note that they can not exclude that living elephants can produce low-frequency "murchanie" by Cat mechanism, but it is obvious that we elephant infrasound can occur without it.