CONCEALING COLORATION 29 



further off he is the more of this scrub actually comes between him and 

 the spectator. There is therefore obviously some distance at which he 

 is wholly covered by the scrub. Now from the very nose of the beholder 

 all the way to the point where the animal is actually hidden by accumu- 

 lated twiggery there is a scale of diminishing visibility, and, while the 

 light favors the animal's background-matching, he becomes utterly indis- 

 tinguishable from the scrub and grass long before he is at the point of 

 actual eclipse. Yet Roosevelt is able to say : " There is never any diffi- 

 culty in seeing them " ! Compare Stewart Edward White's description 

 of the evanescence of deer in similar situations, 4 written before he ever 

 heard of concealing-coloration. 



It is when the light gets behind an animal that its main power to 

 upset concealing coloration comes into play. Except in the middle of 

 the day, there is always one direction which is toward the light, and 

 looked at in this direction the sheltering ambiguities of these thin 

 coverts have to give up many of their secrets. An hour earlier the 

 antelope's imitation twig-haze passed all right, but now that the sun is 

 low and streams through the whole gauzy growth, behold, the opaque 

 antelope becomes a black silhouette on a light gray ground. He is not 

 really a gauzy growth ! 



It is hardly worth while to say that all these laws of light and its 

 relation to vegetation are practically identical the world over. Though 

 I have been through most of Europe, from Norway and England to 

 Italy and Sardinia, and through most of eastern North America, from 

 Quebec to Florida, and in many of the Lesser Antilles and Trinidad 

 (finding everywhere, what I knew before I went, that the laws of illu- 

 mination of animals and vegetation are the same over the whole planet), 

 I have not been in Africa. But — and this is more to the point — my 

 critics have evidently not been in the land of the inexorable optics which 

 govern this entire matter. 



One of Roosevelt's most fundamental errors is his complete gap of 

 perception about the effect of motion on concealing-coloration. In our 

 book's introduction I say : " Thus at these crucial moments in the lives 

 of animals, when they are on the verge of catching or being caught, sight 

 is commonly the indispensable sense. It is for these moments that their 

 coloration is best adapted, and, when looked at from the point of view 

 of enemy or prey, as the case may be, proves to be obliterative." Had 

 our critics studied this sentence, it would have saved them much mis- 

 apprehension of what the book is about. But here let it suffice to 

 remind them that the tennis-player's need of bright, clean, white balls, 

 to be seen against the green turf, entirely refutes their ideas. The 

 tennis-player calls for clean balls when the grass-stained ones are begin- 

 ning to spoil his play; and well might a hawk, if his call would avail, 



4 ' ' The Mountains, ' ' Chapter X., On Seeing Deer. 



