138 AFRICAN GAME ANIMALS 



concealing, others a coloration which is revealing — often 

 strikingly advertising — but neither seems to have any effect 

 upon their lives or their actions. If in cover they all try to 

 escape observation at times by remaining motionless, and 

 most of them in addition at such times crouch flat to the 

 ground. If on the plains, and especially when coming to 

 drink, they make no effort to escape observation; and all 

 are easily visible. The young, almost all of them, crouch 

 flat and motionless to escape observation, and seem to suc- 

 ceed equally well whether, as is generaUy true, they are 

 monotinted substantially like the parents or are spotted 

 in the way that it is possible the adult ancestral form was 

 spotted. The prongbuck uses the white hairs on the rump 

 in a way that looks as if designed for advertisement, and 

 the white tails and white rumps of some of the animals have 

 a marked advertising effect; it is possible that they may 

 serve as signal marks for the young; but if so it is to be 

 remarked that the young of the kinds without these signal 

 marks seem to thrive equally well. We believe that certain 

 general tints common to most of the animals of a given type 

 of country — the pallidity of desert forms, the lustreless 

 darkness of forms of a cold, humid region — are probably 

 due to the inheritance of characteristics acquired by the 

 animals because of the effect of the climatic conditions on 

 all the individuals, generation after generation. Aside from 

 this, we have found no proof that the colors and markings 

 are due to the inheritance of acquired characteristics. In 

 no case do we believe that any particular pattern or color 

 of the big game is due to its survival value, and, therefore, 

 to its production for concealing or revealing purposes by 

 natural selection. As regards most of these animals, the 



