Darwin s Theory of Sexual Selection 169 



a numerous progeny, but for the presence of better-endowed 

 males. We may infer that this would be the case, because 

 the females, which are unarmed and unornamented, are able to 

 survive and procreate their kind. Secondary sexual charac- 

 ters of the kind just referred to will be fully discussed in the 

 following chapters, as being in many respects interesting, 

 but especially as depending on the will, choice, and rivalry of 

 the individuals of either sex. When we behold two males 

 fighting for the possession of the female, or several male birds 

 displaying their gorgeous plumage, and performing strange 

 antics before an assembled body of females, we cannot doubt 

 that, though led by instinct, they know what they are about, 

 and consciously exert their mental and bodily powers." 



This general statement gives an idea of the class of phe- 

 nomena that Darwin proposes to explain by the theory of sex- 

 ual selection. The close resemblance between this process 

 and that of artificial selection may be gathered from the fol- 

 lowing statement : — 



" Just as man can improve the breed of his game-cocks by 

 the selection of those birds which are victorious in the cock- 

 pit, so it appears that the strongest and most vigorous males, 

 or those provided with the best weapons, have prevailed 

 under nature, and have led to the improvement of the natural 

 breed or species. A slight degree of variability leading to 

 some advantage, however slight, in reiterated deadly contests 

 would suffice for the work of sexual selection ; and it is certain 

 that secondary sexual characters are eminently variable. Just 

 as man can give beauty, according to his standard of taste, to 

 his male poultry, or more strictly can modify the beauty orig- 

 inally acquired by the parent species, can give to the Sebright 

 bantam a new and elegant plumage, an erect and peculiar car- 

 riage — so it appears that female birds in a state of nature have, 

 by a long selection of the more attractive males, added to their 

 beauty or other attractive qualities. No doubt this implies 

 powers of discrimination and taste on the part of the female 



