Researchers have just discovered that mice have a unique way of making ultrasonic sounds. These high frequency vocalizations are mostly used as mating calls. The findings are in a paper that was just published in the journal Current Biology.
Mice communicate with high pitched noises and some of these vocalizations are at a frequency not detectable by humans. Their ultrasonic songs are generally used for courting behaviors but are sometimes used in territorial disagreements. Researchers study the songs because it allows them to discover how different drugs may affect mouse vocalizations. For example, scientists want to know when the songs change if they’re testing autism treatments or speech disorders. While researchers had known about mouse songs for a long time, scientists were unsure how the animals created these noises.
Researchers from Washington State University collaborated with laboratories in Denmark and the United Kingdom. The research team used high-speed video to determine how mice make their ultrasonic calls. They were surprised to find that the rodents weren’t vibrating vocal folds in the larynx, like most animals, to create the noises. Instead, mice push a tiny jet of air from the windpipe onto the laryngeal inner wall. The jet of air hits the wall of the larynx and creates a very high frequency whistle. The research team notes that this technique has never been seen in an animal. In fact, this unique mechanism is currently only seen in jet engines.
Mice use a novel method to produce ultrasonic noises when courting mates. Their technique of pushing a stream of air onto the inner wall of the larynx has never been seen in an animal. The findings will provide new insights into mouse vocalizations, helping researchers understand how different drugs affect speech. When testing a medication for stuttering, for example, researchers need to know how it affects mouse songs. The research team believes their research will help scientists develop better methods for studying speech disorders and autism.
Mahrt et al. Mice produce ultrasonic vocalizations by intra-laryngeal planar impinging jets. Current Biology (2016).