Under the cover of darkness in the mountainous forests of East Asia, Chinese pygmy mice emerge from the trees to scurry about the branches and forest floor, scarfing up berries, seeds, and insects. What makes this remarkable is that these animals are almost completely blind.

So how do they get around? New research published today in the journal Science shows conclusively that they echolocate: the mice get a sense of their surroundings and navigate by sending out high-frequency squeaks, then listening for the echoes that bounce off nearby objects. 

Previous work suggested that another tree-climbing relative in the same genus, the Vietnamese pygmy dormouse, could likely echolocate. But this is the first study to pull together various lines of