Rama [creativecommons license] via Wikimedia CommonsLike many rodents, male mice (Mus musculus) produce ultrasonic vocalizations (USVs) when they encounter females or the scent of females. The squeaks are attractive to female mice, which can discriminate between calls of siblings and those of unrelated males. These characteristics suggest that the ‘songs’ play a part in courtship and mating, but their content and function have remained something of a mystery. To find out what all the squeaking is about, Frauke Hoffmann and colleagues Kerstin Musolf and Dustin J. Penn at the Konrad Lorenz Institute of Ethology, Veterinary University of Vienna (Austria) decided to listen in on the USVs of wild mice.