214 THE EVOLXJTIOAT THEORY 



difficult, and that as yet there is very little that can be said with 

 certainty on this point. But there are, after all, some precise 

 observations on mammals and birds which prove that the female 

 shows active inclination to, or disinclination foi-, a particular male. If 

 we hold fast to this fact, and add to it that the distinctive markings 

 of the males are wonderfully developed during the period of court- 

 ship, and are displayed before the females, and that they only appear 

 in mammals, birds, amphibians, and fishes at the time of sexual 

 maturity, it seems to me that there can be no doubt that they are 

 intended to fascinate the females, and to induce them to yield them- 

 selves to the males. The opponents of the theory of sexual selection 

 attach too much importance to isolated cases ; they imagine that each 

 female must make a choice between several males. But the theory of 

 sexual selection does not demand this, any more than the theory 

 of natural selection requires the assumption that eveiy individual of 

 a species which is better equipped for the struggle for existence must 

 necessarily survive and attain to reproduction, or, conversely, that the 

 less well equipped must necessarily perish. 



All that the theory requires is, that the selective and eliminative 

 processes do, on an average, secure their ends, and in the same way the 

 theory of sexual selection does not need the assumption that every 

 female is in a position to exercise a scrupulous choice from among 

 a troop of males, but only that, on an average, the males more 

 agreeable to the females are selected, and those less agreeable rejected. 

 If this is the case, it must result in the male characters most attrac- 

 tive to the females gaining preponderance, and becoming more and 

 more firmly established in the species, increasing in intensity, and 

 finally becoming a stable possession of all the males. 



When we go more into details we shall see that the 2Mrticular 

 qualities of the distinctive masculine characters are exactly such 

 as they would be if they owed their existence to processes of selec- 

 tion; in other words, from this point of view the phenomena of 

 the decorative sexual characters can be understood up to a certain 

 point. It seems to me that we are bound to accept the process of 

 sexual selection as really operative, and instead of throwing doubt 

 upon it, because the choice of the females can rarely be directly 

 established, we should rather deduce from the numerous sexual 

 characters of the males, which have a significance only in relation 

 to courtship, that the females of the species are sensitive to these 

 distinguishing characters, and are really capable of exercising 

 a choice. 



In my mind at least there remains no doubt that the ' sexual 



