NATURAL SELECTION 1491 



one sex to be modified in relation to the other sex, 

 as commonly occurs. This leads me to say a few 

 words on what I have called Sexual Selection. This 

 form of selection depends, not on a struggle for ex- 

 istence in relation to other organic beings or to ex- 

 ternal conditions, but on a struggle between the indi- 

 viduals of one sex, generally the males, for the pos- 

 session of the other sex. The result is not death to 

 the unsuccessful competitor, but few or no offspring. 

 Sexual selection is, therefore, less rigorous than natu- 

 ral selection. Generally, the most vigorous males, 

 those which are best fitted for their places in nature, 

 will leave most progeny. But in many cases, victory 

 depends not so much on general vigor as on having 

 special weapons, confined to the male sex. A horn- 

 less stag or spurless cock would have a poor chance of 

 leaving numerous offspring. Sexual selection, by al- 

 ways allowing the victor to breed, might surely give 

 indomitable courage, length to the spur, and strength 

 to the wing to strike in the spurred leg, in nearly the 

 same manner as does the brutal cockfighter by the care- 

 ful selection of his best cocks. How low in the scale 

 of nature the law of battle descends I know not; male 

 alligators have been described as fighting, bellowing, 

 and whirling round, like Indians in a war-dance, for 

 the possession of the females; male salmon have been 

 observed fighting all day long; male stag-beetles 

 sometimes bear wounds from the huge mandibles of 

 other males; the males of certain hymenopterous in- 

 sects have been frequently seen by that inimitable ob- 

 server, M. Fabre, fighting for a particular female 

 who sits by, an apparently unconcerned beholder of 



