London, Oct 11 (IANS): Mice court one another with ultrasonic love songs that are inaudible to the human ear, and researchers, including one of Indian origin, have found that when mice 'sing', they use a mechanism similar to that seen in the engines of supersonic jets.

"Mice seem to be doing something very complicated and clever to make ultrasound," said study co-author Anurag Agarwal from University of Cambridge. 

Mice, rats and many other rodents produce ultrasonic songs that they use for attracting mates and for territorial defence. These 'singing' mice are often used to study communication disorders in humans, such as stuttering. 

However, until now it was not understood how mice can make these ultrasonic sounds, which may aid in the development of more effective animal models for studying human speech disorders.

"Mice make ultrasound in a way never found before in any animal," lead author of the study Elena Mahrt from the Washington State University noted.

The new research published in the journal Current Biology showed that mice point a small air jet coming from the windpipe against the inner wall of the larynx, causing a resonance and producing an ultrasonic whistle.

Using ultra-high-speed video of 100,000 frames per second the researchers showed that the vocal folds remain completely still while ultrasound was coming from the mouse's larynx.

"This mechanism is known only to produce sound in supersonic flow applications, such as vertical takeoff and landing with jet engines, or high-speed subsonic flows, such as jets for rapid cooling of electrical components and turbines," Agarwal explained.