[Mice] Singing in the Lab

Happy New Year everyone! To celebrate the start of 2011, here is a story from the end of last year: "singing" mice.

These mice, generated by a team of Japanese scientists, vocalize in a manner startlingly similar to that of songbirds. These mice are the product of the University of Osaka's Evolved Mouse Project, which screens mice prone to mis-copying DNA for the presence of random mutations. So far, there are no details as to what exact mutation resulted in these mice exhibiting the song-like vocalizations.

For video of the mice, see this Youtube video.

Interestingly, it appears that non-mutant mice do vocalize extensively, just at ultrasonic frequencies (see this video detailing the research of Dr. Christine Portfors). Could the mutation in the Osaka mice be affecting the frequency of mouse vocalizations, reducing them to levels discernible by human ears? Any commentators out there with greater familiarity in songbird and mouse vocalizations, please sing out in the comments.