A striking revelation of how completely the inconspicuousness of counter- 

 shaded creatures depends upon their counter shading, may be had even more 

 easily than by experimenting with models, merely by holding such a creature 

 upside down, in its normal lighting, and against its normal background. It 

 will be seen not merely that its ghostly dimness has vanished, but that it is 

 extraordinarily conspicuous — ^just doubly as conspicuous, in fact, as any stick 

 or clod placed in the same position would be. For an inverted animal not 

 only lacks counter shading, as a stick or clod does, but is even fully shaded 

 the wrong way — ^brightest where it catches most light, and darkest where it 

 catches least. No other conceivable arrangement of colors could make an 

 object as conspicuous as this. Yet an animal held thus inverted is, materially, 

 as truly "colored like his surroundings" as he ever was. It might be thought 

 that such creatures are usually seen from above, so that their light-colored 

 undersides are out of sight, and that only their upper parts, which always 

 show, are supposed to be colored like their surroundings. To this there are 

 two cogent answers: In the first place, many of these creatures, such as the 

 various forest Grouse, are at their best when perched high above the ground, 

 so that the under side is at least as fully exposed as the upper. In the second 

 place, the colors of those which stay on the ground must surely serve as a 

 protection against the ground a-nimals, which move about on their own level, 

 as much as against those which see them from above, as do hawks and men. 

 This last is a very important consideration, with which we shall have to deal 

 again later in the book. 



In speaking of the elements of visibility, I have already referred to the fact 

 that color — apart from light-and-shade — is a secondary factor in the visibility 

 of the 'modeling' of solid objects, and have spoken of the tendency toward 

 a bluish coloring of the more directly sky-lighted portions, and an orange 

 coloring of the reverse ones. The working of this principle on the bodies of 

 animals is very pronounced, and the counter gradation of their tones would 



ornithologist, Mrs. F. H. Eckstorm, has very truly said, that the gorgeous Scarlet Tanager is not 

 conspicuous in the green woods. 



20 



