A selective advantage may come to exist for those individuals who use certain behaviors in a way that is partly different from the norm, thereby changing the norm in a certain direction. Other displays develop from ritualization of intention movements , i.e. incomplete acts, such as turning away or starting to fly. A related example is the development of frowning from protective eyebrow-lowering, which presumably was originally part of more general preparations for attack or defense. Movements may be redirected or displaced from their normal context, repeated unnecessarily, etc. as part of ritualization. The patterns of animal communication seem to be largely, though not entirely, genetically determined.
All vervet monkeys use the same set of warning cries.
However, the particular creatures that evoke them vary from place to place, depending on the local types of predators. Most animals learn to respond appropriately to the warning cries of other species that happen to live near them. A more elaborate form of social evolution occurs in the songs of humpback whales. Lek behavior is a kind of courtship exhibited by many species of insects, birds and mammals. A number of males gather in a defined area, each in his own piece of the space, and engage in competitive mating displays.