One of the difficulties in science is the limited scope of human senses. We can see only a tiny part of the spectrum, we can only hear a tiny subset of possible sounds, and testing chemicals directly with our nose or mouth is problematic. For example, if you ask most people "do mice sang like birds?" They would probably answer no.
Despite the publication date of this article, it's not a joke. Mice do actually sing in a very similar way to songbirds, and we've known about it for around 50 years. The problem is they sing in an ultrasonic frequency, undetectable to anyone without a specialized microphone.
However, scientists are actively researching mouse songs and a group from Duke University has made some interesting discoveries. (via EurekaAlert) While the mouse songs are not as complex as some songbirds, and less flexible, they are more complex than some previously thought. Their repertoire seems to be from a fixed set of patterns, but it does change depending on the context the mice are in.
They were able to make these discoveries through new computational methods of analyzing the songs. It was able to identify and compare different syllables or utterances within a song. Their analysis was also informed by previous work done with bird songs.
Most singing comes from male nice, naturally, attempting to find and entice a female. When male mice detect the female through the smell of their urine, but don't see them, their song is more complex. Once they see a female, they switched to a simpler song; likely as a means of conserving energy and focusing on other kinds of interaction.
Similarly, female mice were more attracted to the complex songs when just played the audio through a speaker. Suggesting that the two songs have two distinct functions, attraction and then courtship. This level of complexity is important, because it implies a more sophisticated level of communication than previously thought.
Which is exciting news because it opens up the possibility of using mice to study human communication. Mouse models of conditions like autism spectrum disorder may have an impact on how mice produce their songs. Various groups from all over the world are already compiling hypersonic recordings of mice into a database. By analyzing the songs of different mouse strains, in different situations, the hope is to discover their full range of vocalizations.
