Rodent Laugh and Sing

Many people are irrationally afraid of rodents. But a growing body of evidence shows that mice and rats are a lot more like us than you ever imagined. Did you know that rodents laugh when tickled? It’s true. They can also feel each other’s pain (or at least see it in each other’s faces) and can even tell the difference between a Picasso and a Renoir.

And a new study shows that male mice break out into song when they want to woo the ladies! (Ordinarily, the freaky serenade is too high-pitched to be heard by humans, but in the video above the pitch has been lowered to make it audible.)

What’s in a song? For the study, researchers at Duke University recorded the vocalizations made by male mice while they spent time with a female mouse, or sniffed a female’s urine. Then the scientists used a special computer program to see how the “syllables” in the songs were strung together.

It turned out that when the males sniffed the urine but couldn’t see the females, their songs were louder and more complex. When paired up with a real-live female, their croons were longer but simpler.

“It was surprising to me how much change occurs to these songs in different social contexts, when the songs are thought to be innate,” study co-author Dr. Erich Jarvis, an associate professor of neurobiology at the university, said in a written statement. “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.”

All about the chase. Jarvis and his colleagues believe the mice invest their energy in “getting the girl,” and then save energy by doing the bare minimum to keep her interested.

“It’s like they make more effort to bring the female nearby. Once she’s within reach, the game is already won and they focus more on mating behaviors,” study co-author Dr. Jonathan Chabout, a neuroscientist at the university, told The Guardian.

In a second part of the experiment, female mice indicated a preference for the complex mating calls over the simple ones — a further indication that complex songs are an effective means of seduction.

Implications for humans? The researchers hope to study the brain areas involved in producing the songs and test whether mice can learn new songs — research which they say might shed new light on communication disorders like autism.

The study was published online April 1 in the journal Frontiers in Behavioral Neuroscience.

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