Multiple factors in the evolution of animal coloration.

Many of the subjects about which biologists disagree concern the interpretation of function. Morphological, physiological and behavioral characters can simultaneously serve several various functions, all of which are subject to natural selection. These may operate synergistically, but when two produce opposing effects, the one possessing the greater survival value at the time is selected. Often a compromise between several different evolutionary functions results. When the functions under consideration are viewed from a wider angle, a synthesis between differing opinions can sometimes be achieved and a greater understanding of the phenomenon obtained. It should be remembered that, even if an adaptation is invoked for only a brief time during the life of its possessor, it might well be selected merely because of its transient value then. This contribution is not a review, nor is it concerned with the biochemistry and physiology of pigmentation. Rather, it is a discussion of some of the diverse functions that have been ascribed to animal colours. A few typical examples are considered, chosen mainly from among tropical animals including human beings.