92 AFRICAN GAME ANIMALS 



ably because It presents a problem the solution of which 

 needs such infinite (and perverse) ingenuity on their part. 

 Recently, a gentleman who observed a zebra in a zoo 

 standing motionless after nightfall has pointed out that it 

 gradually became invisible as the light faded. Of course it 

 did. From actual observation in the field we can testify 

 that on the average an eland or a roan becomes invisible 

 a little sooner as the light fades; and unquestionably this 

 would be true of the unstriped wild ass as compared with 

 the striped zebra. Selous has commented on the same fact 

 in comparing the coloration effects of zebra and oryx (or 

 eland) at night in their native haunts. All these animals 

 are countershaded. The topi, however, is not counter- 

 shaded. It becomes visible farther off than any of them, 

 and remains visible longer as the light grows dull. The 

 wildebeests and sables and the adult male white-withered 

 lechwis and white-eared kobs, because of their dark hues, 

 and in spite of being countershaded, are in their turn a little 

 more conspicuous than the topi under such circumstances. 

 The natural foes of all these animals hunt chiefly by scent, 

 although their great foe, the lion, has very keen sight; and 

 their habits, so far as escaping from their foes is concerned, 

 are substantially the same under like conditions, neither the 

 countershading nor the absence of countershading, neither 

 the conspicuousness nor inconspicuousness of the colora- 

 tion, seeming to have any effect in revealing or concealing 

 them or enabling them to escape from their foes. 



As regards big game, which, when adult, have nothing to 

 fear from birds, and whose mammalian foes are no taller 

 than, or not so tall as, themselves, the beast of prey looks 

 on his quarry from about the same level or from a lower 



