Two mice are seen at the University of Hawaii. Reuters

Mice, like birds, sing to woo potential partners. The fact that mice sing to call their mothers or signal potential mates has been known to scientists for over 50 years, but a new study shows how complex these songs can be.

In the study, published Wednesday in the journal Frontiers of Behavioral Neuroscience, researchers analyzed mouse-song with the same methods they had previously used for bird-song. They looked for changes in the way mice string together “syllables” in their songs, hoping to analyze how the songs changed depending on the situation.

They found that male mice sing louder and string more complex tunes when they can smell unknown female mice, but quieted their performance down when the latter was nearby.

“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,” Erich Jarvis, Duke University researcher and one of the study’s lead authors said in a press release.

“It is clear that the mouse’s ability to vocalize 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.”

The researchers also found that female mice seem to prefer the presence of the louder, more complex sounds to the simpler ones males employ in their presence. The researchers believe that males expend more energy when the female isn’t visible, but once she’s in his sight, he only expends the bare minimum effort, leaving him with more energy to physically pursue her.

"Few people know that mice actually sing, even in the scientific community," Jonathan Chabout, one of the lead authors, told the Washington Post. "It's easy to study birdsong because you can actually hear them. Mice emit ultrasounds, out of human range."

The researchers uploaded their findings to MouseTube, a growing repository of ultrasound vocals produced by mice that is managed by scientists at the Institut Pasteur in Paris.

The authors say they plan to conduct further study to investigate the role that genes and various regions of the brain play in the songs.