River dolphins can whistle, too, sort of

In the most elaborate attempt so far to eavesdrop on Brazil’s pink river dolphins, researchers have detected what may be a counterpart to seafaring dolphins’ whistles.

Jeffrey Podos of the University of Massachusetts in Amherst took underwater microphones when he joined Brazilian researchers in the Mamirau Reserve. They intended to record what scientists had loosely called whistles from Inia geoffrensis.