blue moon

I couldn't help but think of the singing mice in "Babe" when I saw this headline.

Mice appear to woo mates in song Birdlike tunes surprise scientists
Scientists have known for decades that male lab mice produce high-frequency sounds when they pick up the scent of a female mouse, but it turns out those sounds are more complex and interesting than previously thought.

Songbirds may be the Sinatras of the animal world, but male mice can carry a tune too, say Washington University researchers who were surprised by what they heard.

Scientists have known for decades that male lab mice produce high-frequency sounds — undetectable by human ears — when they pick up the scent of a female mouse. This high-pitched babble is presumably for courtship, although scientists are not certain.

"It soon became ... apparent that these vocalizations were not random twitterings but songs," said researcher Timothy Holy. "There was a pattern to them. They sounded a lot like bird songs."

If the analysis by the researchers is confirmed, mice can be added to the short list of creatures that sing in the presence of the opposite sex, including songbirds, humpback whales, porpoises, insects and, possibly, bats.

Holy and co-author Zhongsheng Guo were studying the brain response in male mice to chemical signals emitted by female mice. The mice sounds were not audible without technical amplification. Initially, researchers recorded the sounds with a microphone, stored them in a computer and converted them to an image.

Later, they developed a way to hear the sounds by recording them on tape and reconstructing them four octaves lower. Holy said the mice sounds met two key criteria for song — distinct syllables and recurring themes, "like the melodic hook in a catchy tune."