ABSTRACT
Communication between two animals is said to occur when one animal produces a chemical or physical change in the environment that influences the behavior of another. The chemical or physical properties of signals have also been studied, often by chemists and physicists and zoologists. The usual physiological methods are used for studies on mechanisms of production and reception of signals; the usual methods of study in animal behavior are adopted for that aspect. Communication between members of a species, at least for higher animals, infuses every aspect of existence from birth to death. Most young vertebrates react almost at hatching or birth to food and alarm signals of the parents, and these reactions increase in precision and variety as life progresses. The chapter discusses the communication systems into those involved in nonsexual activities and those involved in sexual activities.
