Mice sing soprano, claim scientists
Far from being quiet, mice are soprano singers whose musical talent improves with age, a study has found.
Scientists made ultrasonic recordings of mice and discovered evidence of learned behaviour similar to that seen in birds.
Many features of high-pitched mouse songs, including syllable patterns, changed and became more complex as the animals got older.
US researcher Dr Jasmine Grimsley said: "We concluded that the increased complexity of song suggests that mice may be capable of vocal learning."
Another team of scientists from Japan, who conducted a separate study of mouse song, sided with nature rather than nurture and argued that the vocal sounds were innate. Both papers appear in the online journal Public Library of Science ONE.
Mice are known to sing in two very different situations. Infant mice call to their mothers with song-like sounds when distressed, and male mice serenade females.
The American-led team, which included a British scientist from the Medical Research Council Institute of Hearing Research in Nottingham, compared the songs of mice at different stages of life and found that even the youngest pups produced complex sounds with song-like features such as variations in frequency and timing. As the young mice aged, the complexity of their songs increased.
The Japanese scientists led by Professor Takefumi Kikusui, from Azabu University in Kanagawa, showed that two strains of mice had quite different song types. When mouse pups from one strain were reared by adults from another, their song styles did not change.
Dr Kikusu said: "The fact that the cross-fostered animals sang songs similar to those of their genetic parents suggests that the structure of this courtship sound is under strong genetic control."
Dr Grimsley, from Northeastern Ohio Universities Colleges of Medicine and Pharmacy, insisted the Japanese research had not proven that mouse song was purely genetic. "In our opinion, the jury is still out regarding whether mice do, or do not, exhibit vocal learning," she said.