Researchers reporting online on May 20th in Current Biology have found new evidence that male red-eyed treefrogs communicate with one another in aggressive contests by using vibrations they send through their plant perches. The findings open the door to further study of what has been a neglected channel for vertebrate communication. This infrared video first shows a close-up of a male’s aggressive tremulation display and then shows a contest between two males: the male that begins at the lower right of the frame behaves aggressively, tremulating several times before his opponent retreats. Courtesy Michael Caldwell/Boston University/Cell Press