32 THE POPULAR SCIENCE MONTHLY 



plates of counter-shaded " vanished " models. He does not seem to take 

 in at all the marvelous power of this counter-shading, which can 

 actually efface the thing on which it is painted. And he has an idea 

 that it chiefly affects the lower part of an object — as if it were merely 

 a juxtaposition of dark top to white bottom, instead of a continuous 

 gradation over the animal's entire surface. He says : " But as a matter 

 of fact, the great majority of these mammals, when they seek to escape 

 observation, crouch on the ground, and in that posture the light belly 

 escapes observation, and the animal's color pattern loses very much of, 

 and sometimes all of, the ' full obliterative shading of surface colors ' of 

 which Mr. Thayer speaks." Let Colonel Eoosevelt cover the lower half 

 of one of our " vanished " models, in our book, and see if this cause the 

 upper half to appear ! Or let him cover the lower half of the visible 

 monochrome model, and see if this cause the upper half to d/sappear. 



Two more particularly flagrant errors of Eoosevelt's must be men- 

 tioned. First, his speaking as if an animal's not trying to hide dis- 

 proved his being concealingly-colored. He will in time discover that 

 in a vast majority of instances, the very reverse is the case : that the 

 more an animal doesn't hide, the more nature has to help him by 

 coloring, precisely as in the case of the zebra at the drinking-place, or 

 the humming-bird with his head stuck into a flower, or the flamingo at 

 dawn with his head in the mud. Second, his much-insisted-on idea that 

 if one coloration is a concealer, a different one on an animal of the same 

 general habits isn't. He might just as well apply this objection to the 

 mixed herds of diverse-shaped African game, of which so many species 

 have closely resemblant habits, saying, for instance : " If the zebra is 

 built right for this life, then it is a physical impossibility that the oryx 

 is." Or to the innumerable forest plants, each with its own shape, but 

 with, to the casual eye, identical circumstances. Or, concerning such a 

 company of birds as feed together on the marshes, he should say : 

 "These curlews, plover, and sandpipers live together and eat the same 

 things; but if the curlew's bill is the right shape for his life, the very 

 differently shaped bills of the other species are accidents and not 

 adaptations." This is an old, obsolete method in natural history, hence- 

 forth to be succeeded by pure experimentalism. And I am presenting 

 simply the experimentally established facts of these marvelous back- 

 ground-matchings. Amid sunlit snow and blue shadows the blue jay 

 is exquisitely ' effaced ' by its most perfect matching of each color-note. 

 Likewise the peacock up in a tree, or the wood duck among sunlit 

 water-plants, etc. 5 Each of these facts is here to stay, no matter where 

 it leads us. 



5 One of the many surprises in store for Roosevelt is the potently obliterative 

 character of the summer dress of the male bobolink, when seen from the hawk's 

 viewpoint. 



