250 THE PRINCIPLES OF [Part II. 



lure or excite the female. That these characters are the 

 result of sexual and not of ordinary selection is clear, as 

 unarmed, unornamented, or unattractive males would suc- 

 ceed equally well in the battle for life and in leaving a 

 numerous progeny, if better-endowed males were not 

 present. We may infer that this would be the case, for 

 the females, which are unarmed and unornamented, are 

 able to survive and procreate their kind. Secondary sex- 

 ual characters of the kind just referred to, will be fully 

 discussed in the following chapters, as they are in many 

 respects interesting, but more especially as they depend 

 on the will, choice, and rivalry of the individuals of either 

 sex. When we behold two males fighting for the posses- 

 sion of the female ; or several male birds displaying their 

 gorgeous plumage, and performing the strangest antics 

 before an assembled body of females, wq cannot doubt 

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

 about, and consciously exert their mental and bodily 

 powers. 



In the same manner as man can improve the breed of 

 his game-cocks by the selection of those birds which are 

 victorious in the cockpit, 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. Through 

 repeated deadly contests, a slight degree of variability, 

 if it led to some advantage, however slight, would suffice 

 for the work of sexual selection ; and it is certain that 

 secondary sexual characters are eminently variable. In 

 the same manner as man can give beauty, according to 

 his standard of taste, to his male poultry — can give to the 

 Sebright bantam a new and elegant plumage, an erect and 

 peculiar carriage — so it appears that in a state of nature 

 female birds, by having long selected the more attractive 

 males, have added to their beauty. No doubt this im- 



