US researchers say that mice may have the ability to learn songs based on the sounds they hear. They found that when male mice were housed together they learned to match the pitch of their songs to each other. Mice also share some behavioural and brain mechanisms involved in vocal learning with songbirds and humans, say the researchers. But some scientists are sceptical, saying the evidence doesn't support the claim. Details of the study are published in the Journal, Plos One. Previous research in this field has shown that male mice can sing complex songs when exposed to females and these play an important part in courtship. These murine serenades are ultrasonic. At between 50 and 100KHz, they are far above the hearing range of humans. When processed to make them audible to humans, they sound like a series of plaintive whistles.