APPENDIX E 553 



extremes; its ultra-adherents taking up a position like that of some of 

 the earlier champions of the glacial theory; who, having really discov- 

 ered notable proofs of glacial action in parts of Europe and North America, 

 then went slightly crazy on their favorite subject, and proceeded to find 

 proofs of glacial action over the entire world surface, including, for in- 

 stance, the Amazon Valley. As regards many of the big game animals, 

 at any rate, which are claimed by the ultra-exponents of the protective 

 coloration theory as offering examples thereof, there is not the least parti- 

 cle of justification for the claim. 



I select Mr. Thayer's book because it is a really noteworthy book, 

 written and illustrated by men of great ability, and because it contains 

 much that is of genuine scientific value.* I have no question whatever, 

 for instance, that concealing coloration is of real value in the struggle 

 for existence to certain mammals and certain birds, not to mention in- 

 vertebrates. The night hawk, certain partridges and grouse, and numer- 

 ous other birds which seek to escape observation by squatting motionless, 

 do unquestionably owe an immense amount to the way in which their 

 colors harmonize with the surrounding colors, thus enabling them to lie 

 undetected while they keep still, and probably even protecting them some- 

 what if they try to skulk off. In these cases, where the theory really 

 applies, the creature benefited by the coloration secures the benefit by 

 acting in a way which enables the coloration to further its concealment. 

 A night hawk, or a woodcock, or a prairie chicken, will lie until nearly 

 trodden on, the bird showing by its action that its one thought is to es- 

 cape observation, and its coloration and squatting attitude enabling it 

 thus to escape observation; as Mr. Beddard puts it in his book on "Ani- 

 mal Coloration," "absence of movement is absolutely essential for pro- 

 tectively colored animals, whether they make use of their coloration for 

 defensive purposes or offensive purposes." So far as Mr. Thayer's book 

 or similar books confine themselves to pointing out cases of this kind, and 

 to working on hypotheses where the facts are supplied by such cases, they 

 do a real service. But it is wholly different when the theory is pushed 

 to fantastic extremes, as by those who seek to make the coloration of 

 big game animals such as zebras, giraffes, hartebeests, and the like, pro- 

 tective. I very gravely doubt whether some of the smaller mammals 

 and birds to which Mr. Thayer refers really bear out his theory at all. 

 He has, for instance, a picture of blue jays by snow and blue shadow, 

 which is designed to show how closely the blue jay agrees with its sur- 

 roundings (I would be uncertain from the picture whether it is really blue 

 water or a blue shadow). Now it is a simple physical impossibility that 

 the brilliant and striking coloration of the blue jay can be protective 

 both in the bare woods when snow is on the ground and in the thick 

 leafy woods of midsummer. Countless such instances could be given. 



* In passing I wish to bear testimony to the admirable work done by various mem- 

 bers of the Thayer family in preserving birds and wild life work so admirable that if 

 those concerned in it will go on with it they are entitled to believe anything in the world 

 they wish about protective coloration! 



