Behavior is what animals do and why they do it. Behavioral ecology examines the evolution of behaviors that allow animals to adapt to and thrive in their habitats.

There are two broad categories of behavior—learned and instinctive. Instinctive behavior is a pattern passed genetically from one generation to the next. A spider, for example, never needs to see another spider weave a web to know exactly how, where, and when to do it. This information is carried innately with the spider and allows it to carry out many of its life processes without ever having to think about them. The disadvantage to instinct is that is inflexible and does not allow the animal to change when the behavior is no longer appropriate. The armadillo's instinctive upward leap when threatened worked fine until the animal encountered a new environmental hazard—the automobile. Learned behavior, in contrast...