Two species of mouse in Costa Rica has been discovered to be capable of singing, attracting scientists; nobody had really thought that mice had musical tendencies before.

The two species of singing mice ara native to the mountains of Costa Rica: The Alston's Singing Mouse and the Chiriqui Singing Mouse. 

Biologist Bret Pasch devoted three years of his life to capturing, studying, and releasing around hundreds of these singing mice in order to know what these type of mice were singing about, and why. He is currently with the University of Texas, working on, and publishing papers on these singing mice of Costa Rica and Panama.

His Initial research had shown that male singing mice have songs  that involve trilling at pitches so high that humans are unable to hear. 

So what would be the reason behind the mice's singing?

If the conditions are right, and the song is sweet enough, the male singing mice just might win a mate. But several other species use singing to woo their females; birds, whales, humans...but is the mouse-song only intended for the pretty little she-mice?

According to Pasch's research, the singing mice also sing as a means of warning others to stay away from their territory. 

Between the Alston singing mouse and the Chiriqui singing mouse, which both share more or less the same living habitat and the same food source. The Alston mouse is, however, is smaller and more timid than the aggressive Chiriqui mouse. When the CHiriqui starts singing, the any Alston's mouse in the area would hastily flee. 

Further studies have shown that despite the singing mice not having the physiological features to enable them to sing, they instead learn how to do it themselves via auditory feedback wherein they learn to sing whenever they hear someone else. For example, it was shown that male mice performed better when in the same room with a female. 
Pasch says his study does not end with these forest mice; he says even domesticated rodents rats and hamsters "produce complex vocalizations."