Animal behavior is the scientific study of everything animals do.
It involves investigating the relationship of animals to their physical environment as well as to other organisms, and includes such topics as how animals find and defend resources, avoid predators. People who study animal behavior are concerned with understanding the causes, functions, development, and evolution of behavior. The causes of behavior include both the external stimuli that affect behavior, and the internal hormonal and neural mechanisms that control behavior. The functions of behavior include its immediate effects on animals and its adaptive value in helping animals to survive or reproduce successfully in a particular environment. The development of behavior pertains to the ways in which behavior changes over the lifetime of an animal, and how these changes are affected by both genes and experience.