232 MY SOMALI BOOK 



As time went on the lion, finding it more and more 

 difficult to capture his prey, would often find that it 

 was only in the dusk, after going hungry all da}^, that 

 he achieved success. A crepuscular habit once acquired 

 and accompanied by a gradually increasing power of 

 vision in a dim light, would develop almost inevitably 

 into a nocturnal one. The antelope or zebra meanwhile 

 would develop still more its ]3owers of scent and perhaps 

 hearing, and, in the case of the latter, become more 

 and more wholly a denizen of the plains. 



Similarly the wolves and wild dogs acquired 

 nocturnal habits, though perhaps in a less degree ; 

 they did not, however, attain to the superlative stealthi- 

 ness of the cat tribe, but in compensation developed 

 their power of hunting by scent. 



And so we are brought down to the conditions of 

 to-day, where the colouring of many species is such 

 that, whether in the present or in somewhat different 

 surroundings in the past, it would have an undoubtedly 

 protective effect against an enemy hunting by sight 

 in the daytime. Where there has been a later change 

 of colour, the need for colour-protection having passed 

 aAvay, we may with a measure of confidence put it 

 down to the influence of a change of environment. 



Much as its importance has diminished, as a factor 

 in the struggle for existence, I do not believe that 

 protective colouration has ceased to be of value in the 

 case of all the larger mammals. The lesser kudu, for 

 instance, living in thick jungle, is probably subject, 

 not infrequently, to the attacks of the leopard in the 

 daytime ; while the chita is known often to hunt by 

 da}^ And at night it is be^^ond question that some 



