Page:Popular Science Monthly Volume 84.djvu/411

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SEXUAL SELECTION
407

Nor can it be held that warning coloration depends upon the intelligence of the warned individual. Certain mimic butterflies may have only a superficial resemblance to each other, but the resemblance is sufficiently close to save the mimic from attack by the animals which spare the mimicked forms. Birds are not close critics or students of certain types of color patterns. A more critical observer would not be so easily deceived.

These considerations are wholly independent of the origin of mimicry. Conceivably, there have been cases arising in nature in which one species has developed certain characters which render it unfit for food; and another species, which may develop a color pattern similar to that of the noxious form, has been spared because of this resemblance. But all cases of supposed mimicry are not necessarily of this sort. As Eigenmann[1] has shown, many cases which might, under other conditions, have passed for mimicry are really cases of convergent or parallel evolution, the similarities arising from similar responses of different organisms to the same or similar features of the environment. Indeed, Eigenmann's position seems especially strong, since he is able to supplant the hypothesis of mimicry, wherever it is weak, by the more general theory of natural selection. But the essential point to be kept in mind in this connection is that, no matter how the resemblances may have arisen, if mimicry protects at all, the mimic escapes because of the lack of a keenly critical faculty in the pursuer.

An animal of a low grade of intelligence is more apt to show uniformity of deportment than an animal of a higher grade. The frog has never rivaled either the serpent's or the owl's reputation, possibly undeserved, for wisdom, but it reacts to a red rag with avidity. A really intelligent animal would not be so easily humbugged. A contraption of feathers, gay colors and steel wire will lure a trout from his pool, often to his sorrow, but the deception in the hands of competent deceivers proceeds from year to year. Any skillful angler will verify the statement that it is the trifling things which are of importance in the pursuit of fish. The catfish is more prosaic and demands more of the reality in the form of worms, not being satisfied with the mere semblance of food.

The arguments which apply to warning coloration apply equally well to sexual selection, and it is clear from what has been said that neither sexual selection nor warning coloration require any great amount of intelligence on the part of the warned individuals or the pleased ones. Indeed, it is conceivable that both processes might act more strongly in animals which were not too intelligent. In man, financial, social and family considerations often outweigh the more natural considerations.

  1. Eigenmann, Annals of the Carnegie Museum, 1909-10, VI., pp. 4-54, and later papers.