Female mice sing back for sex

While it is known that male mice belt out something like love songs to females when the time seems right to them, new research has found that interested female mice sing back their consent.

The researchers gathered data as four mice -- two males, two females -- were observed interacting. They detected vocal exchanges during chases when a male pursued a female.
The data showed that females who responded vocally to a male's "song" also slowed down, making it easier for the male to catch up to them. Unresponsive females kept up their pace.

"You cannot tell that a mouse is singing or shouting. There is no obvious physical sign. And their voices during these interactions register in a range far beyond the reach of human ears, said one of the researchers Joshua Neunuebel, assistant professor of psychological and brain sciences at  University of Delaware in the US.

The highest range the human ear can detect is about 20 kilohertz. The high-pitched voice of a mouse registers at about 35 to 125 kilohertz, he said.

Neunuebel developed sophisticated array of microphones and a software for sound analysis that allowed researchers to figure out -- with up to 97 percent accuracy -- which sound came from which mouse.

That is when they discovered that female mice were not just listening to male voices. They were singing back.

The findings were detailed in the journal eLife.