298 SEXUAL SELECTION: MAMMALS. (Tart II. 



In these and many other monkeys, the beauty and 

 singular arrangement of their colors, and still more the 

 diversified and elegant arrangement of the crests and 

 tufts of hair on their heads, force the conviction on my 

 mind that these characters have been acquired through 

 sexual selection exclusively as ornaments. 



Summary. — The law of battle for the possession of the 

 female appears to prevail throughout the whole great 

 class of mammals. Most naturalists will admit that the 

 greater size, strength, courage, and pugnacity of the male, 

 his special weapons of offence, as well as his special means 

 of defence, have all been acquired or modified through 

 that form of selection which I have called sexual selec- 

 tion. This does not depend on any superiority in the 

 general struggle for life, but on certain individuals of one 

 sex, generally the male sex, having been successful in 

 conquering other males, and on their having left a larger 

 number of offspring to inherit their superiority, than the 

 less successful males. 



There is another and more peaceful kind of contest, 

 in which the males endeavor to excite or allure the fe- 

 males by various charms. This may be effected by the 

 powerful odors emitted by the males during the breeding- 

 season ; the odoriferous glands having been acquired 

 through sexual selection. Whether the same view can 

 be extended to the vo^ice is doubtful, for the vocal organs 

 of the males may have been strengthened by use during 

 maturity, under the powerful excitements of love, jealousy, 

 or rage, and transmitted to the same sex. Various crests, 

 tufts, and mantles of hair, which are either confined to 

 the male, or are more developed in this sex than in the 

 females, seem in most cases to be merely ornamental, 

 though they sometimes serve as a defence against rival 

 males. There is 'even reason to suspect that the branch' 



