BBC Nature Wild Video Collection. Acoustic communication is the sending and receiving of messages using sound. Bird song, the roars of lions and the chirping of cicadas are all examples of this. Sometimes the messages are outside the range of human hearing, such as the ultrasonic squeaks of baby rats or the infrasound rumbles of elephants. Most acoustic communication is not language, in the sense that humans use it, although language is one aspect of this adaptation.
There are 50 videos on animal communication archived on this BBC site.