Male mice woo mates by singing

Male mice court their mates with love songs, and not just in cartoons, according to researchers at Washington University.

What do mice have in common with whales, frogs, insects, bats, birds and humans? They court their mates with love songs, and not just in cartoons, according to researchers at Washington University in St Louis.

It's long been known that male mice react to the seductive pheromone odours of females by producing ultrasonic tones. Even the human ear can discern some of their squeaks and chatters.

But now, according to an article published in the Public Library of Science Biology, an online science journal, the ultrasonic tones have a form and pattern that meet the definition of 'song'.

The researchers used cotton swabs coated with female and male mouse urine to elicit the sounds, then recorded the vocal responses. To analyse the sounds, they used electronic tricks in the studio to coax out the sound for human ears. At one point, they played the tones at one-sixteenth of the recorded speed.

The result? Mouse song is actually similar to bird song.

'The males produced rapid 'chirp-like' syllables of varying duration, spaced at about 10 syllables a second, with a burst of closely spaced syllables followed by periods of silence,' an abstract of the article said.

The researchers found that the sounds were not random, but rather followed a stereotyped pattern. The trial was repeated on 45 different mice.

'Since the mice produced multiple syllable types arranged in regular, repeated time signatures, their vocalisations meet the definition of song,' the abstract said.

The researchers, Timothy E Holy and Zhongsheng Guo, wrote that the 'richness and diversity of mouse song appear to approach that of many songbirds'.

And just like songbirds, each mouse was singing its own tune.