COLORATION 81 



and they see things accordingly. At another time they are 

 taught the extreme efficacy of stripes, and accordingly any 

 time a striped animal proves hard to see, the fact is stored 

 away in support of the theory. 



In Sclater and Thomas's " Book of Antelopes," Lieuten- 

 ant-Colonel Olivier says of the lesser koodoos of the Somali- 

 land region that they are found in "thick, scrubby jungle," 

 and he dwells on the way in which the stripes on the slaty 

 gray of their coats make them "harmonize with the foliage" 

 and "exactly reproduce the checkered shade of sunshine 

 through leaves." Writing of the gerenuk of the same re- 

 gions, Donaldson Smith says: "Their solid reddish brown 

 color renders them almost invisible . . . they almost always 

 keep to the bushes." The two observations seem incon- 

 sistent; but they are not; it is only the implied explanations 

 that are inconsistent. A solid reddish-brown, and a slaty 

 gray with white stripes, are not in the least alike; yet the 

 wearers of both coats, in substantially the same country, are 

 exceedingly and equally difficult to see — as we ourselves dis- 

 covered on the Guaso Nyiro, where both species are found 

 under substantially the same conditions. The fact is that 

 it is neither the stripes nor the absence of stripes, neither 

 the reddish-brown nor the slaty gray, that is concealing. 

 Any color, or combination of colors, any solid-colored coat 

 or striped or spotted or varied coat — save, perhaps, some 

 highly advertising color like pure black or pure white, or 

 such a combination as a black back and a white belly — is 

 concealing in such cover to an animal with such habits. 

 Cover and habit are the essentials; the exact shade of, or 

 amount of variety to, the coat is of no consequence. Nat- 

 ural selection cannot have produced either coat under pres- 



