Singing Mice Protect Their Turf with Song in Mountain Cloud Forests (Video)

Did you know that some mice sing? Two species of tawny brown singing mice live deep within the mountain cloud forests of Coast Rica and Panama. Now, scientists have discovered that these mice sing in order to protect their turf.

Researchers knew before that the males of these two species sang in order to attract mates and repel rivals. They didn't realize, though, that these species also sang in order to create geographic boundaries. That seems to be the case, though. It turns out that the smaller Alston's mouse steers clear of its larger cousin, the Chiriqui, when it hears its call.

"Most people are puzzled by the existence of singing mice, but in reality many rodents produce complex vocalizations, including mice, rats and even pet hamsters," said Bret Pasch, one of the researchers, in a news release. "Often they're high-pitched and above the range of human hearing."

The Alston's singing mice are smaller and more submissive in comparison to Chiriqui singing mice. They also have longer, higher-pitched songs. Yet both of the mice produce songs that are barely audible to humans due to their high pitch. While both species of mice share similar diets and live in similar forest habitats, though, they somehow avoid overlapping.

In order to examine these mice a bit more closely, the researchers went into the field. They discovered that temperature regimes determine how far down the mountain the larger Chiriqui mice can spread; they do not tolerate heat well and prefer higher altitudes with cooler temperatures. In contrast, the temperature-tolerant Alston's mice will readily spread higher into cooler habitats if the larger Chiriqui mice are removed.

Despite this, though, Alston's mice avoid Chiriqui mice. Whenever they hear the call of the bigger mice, they will cease singing and instead flee to avoid confrontation.

"The use of communication in mediating species limits is the major finding of our study and provides insight into how large-scale patterns are generated by individual interactions," said Pasch.

The findings are published in the journal The American Naturalist.

Want to see a singing mouse for yourself? Check out the video below, courtesy of Vimeo.

Alston's singing mouse (Scotinomys teguina) calling in the clouds from bpasch on Vimeo.