Michael Schöner of the University of Greifswald in Germany and his colleagues bounced sonar waves off the rear inner wall of the pitcher plant Nepenthes hemsleyana and found that it reflected the sound much more clearly and strongly than did other species of pitcher plant. When they modified or removed the sound reflector, wild Hardwicke's woolly bats (Kerivoula hardwickii; pictured) took much longer to find the plant.