362 EVOLUTION, GENETICS, AND EUGENICS 



costumes being, in their own way, climaxes of obliterative coloration 

 scarcely surpassed even by moths or by inchworms. 



"This discovery that patterns and utmost contrasts of color (not 

 to speak of appendages) on animals make wholly for their 'obliteration,' 

 is a fatal blow to the various theories that these patterns exist mainly 

 as nuptial dress, warning colors, mimicry devices (i.e., mimicry of one 

 species by another), etc., since these are all attempts to explain an 

 entirely false conception that such patterns make their wearers con- 

 spicuous. So immeasurably great, in the case of most animals, must 

 be the value of inconspicuousness, that such devices as achieve this to 

 the utmost imaginable degree, upon almost every living creature, de- 

 mand no further reason for being (although doubtless serving count- 

 less minor purposes) Apparently, not one 'mimicry' mark, nor 



one 'warning color' or 'banner mark' nor one of Gadow's light-and- 

 shadow-begotten marks, nor any 'sexually selected' color, exists any- 

 where in the world where there is not every reason to believe it is the 

 very best conceivable device for the concealment of its wearer, either 

 throughout the main part of this wearer's life, or under certain pecu- 

 liarly important circumstances The so-called 'nuptial' cos- 

 tumes of animals are demonstrably an increase of such potency of 

 obliterative coloration as belongs to all gorgeously varied costumes, 

 and this at the very period when concealment is most needed." 



Thayer believes "that the colors, patterns, and appendages of 

 animals are the most perfect imaginable effacers under the very cir- 

 cumstances wherein such effacement would most serve the wearer." 

 Many animals, when observed in a museum show case or in a menag- 

 erie, appear to us to be most conspicuous, but the elements that lend 

 conspicuousness in the artificial environment may be the very ones 

 that tend to efface the wearer when in his native haunts. The most 

 brilliant birds, such as mandarin ducks, birds of paradise, flamingoes, 

 peacocks, parrots, etc., are shown to be almost invisible in their 

 natural surroundings. 



The schemes for producing obliterative protection are much the 

 same as those made use of during the recent war. The simplest scheme 

 oi all is that of having the same color and pattern as the background. 

 Thus many green insects, amphibia, reptiles, birds, and a few mammals 

 that live in trees, smaller plants, or grass, are colored green. Many 

 desert animals are sand colored. Many marine animals living near 

 the surface are transparent or nearly so. Another scheme is known 

 as counter-shading, according to which most animals with little variety 



