MOSCOW, 11 Dec – RIA Novosti. Ultrasonic “Serenade” mice, rats and other rodents, and they attract the opposite sex, and develop them using the same mechanism that gives the jets their characteristic high-frequency “whistle”, according to a paper published in the journal Current Biology.
“We found that mice emit ultrasonic signals unique to animals. They do not use vibrating vocal cords and force a thin stream of air coming from their lungs, to hit the inner part of the larynx. As a result, born an ultrasonic whistle,” said Cohen Elemans (Coen Elemans) from the University of southern Denmark in Odense.
How can you explain Elemans and his colleagues, something similar takes place inside a jet engine when starting and during takeoff or landing, during which the man standing near the aircraft or sitting within him, could hear the characteristic whistles and “whine”. The same effect generated by the flow of air at supersonic speed, used today by engineers to cool the computers and optimize the operation of turbines.
The discovery that mice sing as well as “growl” jet engines, it was a surprise to the scientists – they believed that the ultrasonic trills mice arise due to the special “Palatnik” vibrations in their vocal cords or due to the biological analogy of how the whistle of the kettle. In the role of “whistle” was to speak, as did the biologists to this study, the glottal opening, as well as the voice box or oropharynx.
Watching the passing streams of air through the vocal cords and other parts of the respiratory system of mice with a high-speed camera, made 100 thousand frames per second, the scientists found that both hypotheses did not explain what was really going on.
For example, removal of the epiglottic cartilage or ligaments did not lead to the disappearance of ultrasound, whereas destruction of thyroid cartilage, who did not play any role in the birth of a sound in these theories, on the contrary, guaranteed did mice dumb.
As shown by further experiments, this cartilage was a key part in the birth of the “voices” of mice clash with a flow of air coming from the lungs, has created a special set of acoustic waves that have interacted with air flowing down from the vocal cords. As a result of the emergence of a stable and clean ultrasonic pulses, the frequency and power of which the rodent can be manipulated by changing the velocity of the air.
Scientists suggest that a similar mechanism can also be used in other mammals – for example bats, to obtain a relatively stable and clean ultrasonic signals, which are vital to them for echolocation and navigation in the night time.