Evolution

A creature may have fine physical defenses such as hard armor or sharp spines. It may have powerful chemical defenses such as an appalling smell or a foul taste but none of these defenses is much used in the struggle for survival unless the animal also has the right behavior to go with it. Evolution shapes a living creature's size and color, and it also shapes an animal's actions and behavioral patterns. The most important behaviors are instinctive or in-built. In other words, the creatures can perform the actions without having to learn what to do it by trial and error.