Rats can sing like humans
A team of Japanese researchers found that when a male rodent comes across a potential mate, he bursts into a complex series of loud chirps and whistles that sound remarkably like birdsong.
Although the ultrasonic calls are too high-pitched for the human ear to pick up, the researchers said, the "love songs" allow females to weigh up the most suitable father for their offspring, the Daily Mail reported.
However, the researchers were not yet able to find out whether the animals are born with their songs fully formed in their heads, or they learn them from their parents and peers as we do.
Scientists have previously known that mice emit squeaks that are inaudible to humans. In 2005, US researchers discovered that these noises are made up of repeated phrases just like the songs of birds and whales.
Since then, researchers have been trying to find out whether the songs are programmed into the brains of mice from birth, or whether they learn them from their mothers.
Now the Japanese scientists, used two strains of laboratory mice with distinct songs, have found the answer.
Males from each strain were raised in litters of the opposite strain until they were weaned.
At the age of ten to 20 weeks their calls were recorded and analysed.
Dr Takefumi Kikusui, from the Azabu University who led the study, said that the mice sang the songs of their biological parents — not their foster mothers.
The new findings were published in the journal PLoS.