ually selected" color, exists anywhere in the world where there is not every 

 reason to believe it the very best conceivable device for the concealment of its 

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

 peculiarly important circumstances.* 



These deceptive patterns, painted by Nature on the exteriors of almost all 

 animals, will prove to be an inexhaustible field for studying their psychology. 

 Stevenson makes Alan Breck say "Them that cannae tell the truth, should 

 be aye mindful to leave an honest, handy lee behind them. If folk dinnae 

 ken what ye're doing, Davie, they're terrible taken up with it ; but if they think 

 they ken, they care nae mair for it than what I do for pease porridge." The 

 psychological principle in this lies deep in Nature's artifices for concealing 

 animals. Wherever, for instance, the animals are habitually to feed amidst 

 brilliant vegetation, she is apt to give brilliant marks rather than simply equip- 

 ping them to match the soberer interstices amidst the brilliant details. The 

 principle is, evidently, that amidst a large number of similar striking objects, 

 an imitation of these has the support of the credit of all the real ones. There are 

 before the eye so many obviously real ones, that the mind refuses to take the 

 trouble to suspect any. For a red mark on a bird, fish, or butterfly to pass 

 itself off for a red flower among many red flowers is like Alan's telling the 

 passer-by that his errand is such a familiar one as the search for a runaway 

 horse ; while, in such a situation, to try to escape notice by imitating a dusky 

 place, may be as much more risky as for Alan to assert merely that he is not 

 on a mysterious errand. f The so-called "nuptial" costumes of animals are 



* Plainly, most details of an animal's body serve many purposes; and whatever law develops 

 the detail's main characteristics, doubtless causes it also to be modified to meet each minor use, in the 

 degree of its relative importance. To illustrate with human experiences, the hunter's rifle, besides 

 its main use, serves also at times the purpose of a balancing-pole, or even a club; and, carried over 

 his shoulder as he goes away, it serves to show his family that there may be venison for dinner; yet 

 its essential purpose is to kill that venison, — for this, nothing but a rifle would serve. In the same way 

 animals' markings doubtless serve in various lesser degrees most of the purposes that have been 

 attributed to them. 



t Another good analogy is the universal human propensity to trust circumstantial evidence too 

 much; to believe any accused person guilty, because the sin he is accused of is a common one. 



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