From Martin Gregorie
I am not surprised at the recent discovery of singing mice (5 November, p 14), but I am amazed that such behaviour has never been reported for rats. I had a pet hooded lab rat over 30 years ago that when kept in a quiet room could be distinctly heard to sing as it went about its business. The sound was quite clear when the rat was happy and close by.
As this was clearly not ultrasonic song, maybe rats would be more convenient subjects for this research.
From Ian Simmons
The discovery that mice sing would have come as no surprise to radio listeners in the late 1930s, when there was a brief vogue for broadcasting their song.
The most famous of these performers was Mickey, the Singing Mouse of Devonport, and its songs were broadcast on American radio in the company of other singing mice from the US and Canada. Mickey’s vocalisations were described as “a soft whirring trill rising into a crescendo, followed by a two-note jump, tapering to a diminuendo”. A Detroit mouse had its song compared to a robin or a tone-deaf canary.
In his magnum opus on singing mice in Fortean Studies (vol 3), Jonathan Downes collects a wide range of singing mouse reports from newspapers and scientific literature going back to the 19th century. These vocalisations were attributed to respiratory afflictions suffered by the mice, although their singing behaviour suggests otherwise: some could keep it up for hours and others carried out energetic exercise while singing.
Your report of Tim Holy and Zhongsheng Guo’s recent research suggests another origin for the singing. Might those mousey singing stars have been making basically the same vocalisations, only dropped from the ultrasonic to be at a low enough frequency to be audible? Do people still encounter audible singing mice today? Downes records none later than the 1940s and I have not encountered any recent reports either.
Penarth, Vale of Glamorgan, UK
Harlow, Essex, UK