Animal Communication - is the transfer of information from one or a group of animals (sender or senders) to one or more other animals (receiver or receivers) that affects the current or future behaviour of the receivers. Information may be sent intentionally, as in a courtship display, or unintentionally, as in the transfer of scent from predator to prey. Information may be transferred to an "audience" of several receivers. Animal communication is a rapidly growing area of study in disciplines including animal behaviour, sociobiology, neurobiology and animal cognition. Many aspects of animal behaviour, such as symbolic name use, emotional expression, learning and sexual behaviour, are being understood in new ways. When the information from the sender changes the behavior of a receiver, the information is referred to as a "signal". Signalling theory predicts that for a signal to be maintained in the population, both the sender and receiver should usually receive some benefit from the interaction. Signal production by senders and the perception and subsequent response of receivers are thought to coevolve. Signals often involve multiple mechanisms, e.g. both visual and auditory, and for a signal to be understood the coordinated behaviour of both sender and receiver require careful study.