2 8 THE POPULAR SCIENCE MONTHLY 



discovered animals'-costume-scenery-counterfeiter not counterfeiting 

 scenery, is any step at all toward finding out whether they all three 

 do at certain times perform their tricks. Forty years of daily meeting 

 the poacher at the post office does not strengthen his credit. And forty 

 years of Eoosevelt's seeing zebras not hidden by their costume, and fail- 

 ing to guess what the animal's stripes are for, are just as little to the 

 point. 



This effacing machinery is not the only highly specialized mechan- 

 ism that animals carry always with them merely to have ready for occa- 

 sional need. It is just the same with many of their other members and 

 adaptations. The tiger's tremendous claws, if we estimate that he kills 

 only once in two days, and that it takes perhaps four seconds for him 

 to do it, are in operation only a 44,700-th of his life. Would Colonel 

 Roosevelt for want of seeing them at their work decide that it was onlv 

 a theory that they are for pulling down game? (I, by the way, do not 

 even stop at the evidence that animals' costumes are for concealment. 

 I point to the actual concealment in full operation.) The tiger's whole 

 massive steely build serves him scarcely more constantly than do his 

 claws. It, with the claws, does the pulling-down, and adds the bearing- 

 away. The rattlesnake has a heavy rear body, growing slender and 

 agile toward the head end, evidently in order that his terrible poison- 

 apparatus may have a strong base to spring from. All this mechanism 

 serves him only for occasional instants — days, weeks or months apart. 

 Yet, there he always is, a heavy slow snake good only for lying in wait 

 and for these rare murderous lunges, and totally incapable of the 

 arboreal feats and racing of the black-snake's life. Would Eoosevelt, 

 because he so often sees rattlers not biting, hoot at the idea that this 

 snake's fangs and build are made for biting? The generative organs 

 of every monogamous species that breeds only once a year are carried 

 through life for a few moments' function once a year — and so on and so 

 forth. With costumes it is just as with all other adaptations. They 

 may, according to their wearer's habits, play in his life a long part or 

 a short one. 



The particular herds and individuals of plains game that stood out 

 so visible to Colonel Eoosevelt were commonly those that happened to 

 have the light behind them; and wherever any form of tree, shrub or 

 very tall grass constituted an element of the scene, there were sure to be 

 other herds and individuals in directions in which the illumination 

 favored their counter-shading, wholly invisible amidst the haze of 

 scrub and grass. A spectator in such a scene is surrounded with vast 

 reaches of all-engulfing distance into which the haze of interposed scrub 

 growth merges on every side. In these spaces a counter-shaded animal, 

 when the direction of the daylight favors the working of his counter- 

 shading, is already wonderfully matched to the scrub's color, and the 



