Mice 'use music' to seduce partners
Male mice sing like birds to serenade prospective mates, research has shown.
Their musical sounds are too high pitched for humans to hear, but share similarities with the tweets of songbirds and change to suit different social situations.
For more than 50 years it has been known that mice emit "ultrasonic vocalisations", or USVs.
Baby mice produce them when they call for their mother, and the sounds grow more complex as mice reach adulthood. But scientists are still trying to decode the songs and understand what they mean.
The new study found that " surprisingly complex" songs are used in courtship by male mice.
Although their singing ability was more limited than a blackbird or robin's, it was musical. Within a given song, strings of notes followed specific patterns and were not random, the study found.
The mice also appeared able to modify their songs, making them louder and more complex when they could smell a female but not see her.
Longer and simpler songs were chosen when a male was wooing a female in his presence.
Neurobiologist Dr Erich Jarvis, from Duke University in the US, said: "We think this has something to do with the complex song being like a calling song, and then when he sees the female, he switches to a simpler song in order to save energy to chase and try to court her at the same time.
" It was surprising to me how much change occurs to these songs in different social contexts, when the songs are thought to be innate. It is clear that the mouse's ability to vocalise is a lot more limited than a songbird's or human's, and yet it's remarkable that we can find these differences in song complexity."
Females appeared to react differently to different songs, spending more time by speakers playing the more complex tunes.
This is further evidence that the various calls carry meaning, said the researchers.
Next, the scientists plan to investigate the role of genes and brain areas in mouse song.
The research, published in the journal Frontiers In Behavioral Neuroscience, may contribute to better understanding of autism and vocal communication disorders in humans.
"We and other scientists from all over the globe are studying mice to test the limits of vocal learning and plasticity," said Dr Jarvis.
Recordings of the songs have been uploaded to MouseTube, a repository of mouse music set up by scientists at the Pasteur Institute in Paris, France.