Behaviors are actions that an organism engages in—they can be related to finding food, reproducing, defending against threats, and many other possible actions. Behaviors include activities related to the environment around the animal—such as migration—as well as social interactions within a species or population. Many behaviors involve motor output—that is, muscle movements—while others involve less visible actions, such as learning.

Genetic and Environmental Influences

Both genetic and environmental factors influence behavior. For example, some behaviors, such as fixed action patterns, are innate with a strong genetic component. Other behaviors require learning, such as song learning in young birds. Some behaviors, like the imprinting that occurs between some newborn animals and their parents, are a combination of both hard-wired instinct and life experience.

Many behaviors have evolved because they increase fitness. This benefit may be direct, such as a behavior that raises the chance of survival by allowing an animal to find food in a way that optimizes the balance of benefits and costs. Many behaviors, such as careful mate choice, increase the production of healthy offspring and the quality of care for helpless young. Finally, some animals engage in altruistic behaviors by helping close relatives or other members of their social group survive and reproduce.