104 AFRICAN GAME ANIMALS 



bushes round about, and, when on It, both birds lie flat, with 

 outstretched neck, if they suspect danger. It is said that 

 the hen broods by day and the cock by night, but twice we 

 came on cocks brooding by day. Moreover, by moonhght 

 the cock's coloration is almost as conspicuous as by day; 

 and on all nights, if the birds can be seen at all, the cock 

 is most conspicuous. At all times, therefore, including the 

 most vital moments and crises of their lives, the cock's 

 coloration is boldly advertising and that of the hen some- 

 what concealing. Yet the habits of the two are identical. 

 Both have the same foes, the lion and very occasionally 

 the leopard, while the young are in danger from hyenas, 

 jackals, eagles, and big hawks. The birds are monoga- 

 mous, so that the numbers of the sexes are substantially 

 equal; which means that the highly advertising coloration 

 of the cock is of no disadvantage to him in the struggle for 

 existence. Evidently his coloration has not been developed 

 by natural selection or because of any utilitarian purpose, 

 and, equally evidently, the relatively concealing coloration 

 of the hen has no survival value as compared with the cock's 

 coloration. 



The same statement applies to various antelope. The 

 female and young Grant gazelle and the Tommies of all 

 sexes and ages have a lateral black band which is dis- 

 tinctly advertising. The adult male and occasionally the 

 old female Grant gazelle lack the stripe, and their coloration 

 becomes concealing. Yet there is absolutely no difference 

 in habits, and no benefit or detriment is caused by either the 

 presence or the absence of the black lateral band. The adult 

 males of the sable, white-withered lechwi and white-eared 

 kob are advertisingly colored compared with the females; 



