Bioacoustics, the study of production, transmission and reception of sound in animals, has important implications for ecological conservation.

Now all animals with ears hear sound, which is made up of invisible waves that create vibrations in the air. High-pitched sounds make fast vibrations, and low-pitched sounds make slower vibrations.

But mimicking the sounds of animals isn't as easy as woofing or purring. [Marko purring] Though he can do that, too. Picking the right sounds involves carefully examining both objects and surfaces.