A PROBLEM IN HUMAN EVOLUTION. 255 



less condition over the whole body (with trifling exceptions) in the 

 average of all sexes, races, and ages. For this further and complete 

 denudation I think we must agree with Mr. Darwin in invoking the 

 aid of sexual selection, especially when we take into consideration the 

 ornamental and regular character of the hairy adjuncts which man 

 still retains. 



In the first place, we have external reasons for believing that sexual 

 selection has produced similar results elsewhere, acting upon a like 

 basis of natural denudation. For among the mandrills and some other 

 monkeys the naked callosities, originally produced, as is here sug- 

 gested, by physical friction, have been utilized for the display of beau- 

 tiful pigments ; and Mr. Bartlett informed Mr. Darwin that as the 

 animals reach maturity the naked surfaces grow larger in comparison 

 with the size of the body. When we look at the great definiteness 

 and strange coloring of these bare patches we can hardly doubt that 

 they have been subjected to some such selective process. 



But if man once began to lose the hair over the whole of his back, 

 shoulders, and haunches, as well as more partially upon his sides, legs, 

 and arms, he would soon present an intermediate half -hairy appearance 

 which is certainly very ludicrous and shabby-looking. Why this mid- 

 dle stage should displease us, it might be rash to guess ; yet one may 

 remember that as a rule throughout the mammalia a partially hairless 

 body would be associated with manginess, disease, and deformity. At 

 any rate, it seems to be the fact that, when animals once begin losing 

 their hair, they go on to lose it altogether. One may well believe that 

 among our evolving semi-human ancestors those individuals which had 

 most completely divested themselves of hair would be the most at- 

 tractive to their mates ; and these would also on the average be those 

 which had most fully adopted the erect attitude with its accompanying 

 alterations of habit. Thus natural selection would go hand in hand 

 with sexual selection (as I believe it always does), those anthropoids 

 which most nearly approached the yet unrealized standard of humanity 

 being most likely to select one another as mates, and their offspring 

 being most likely to survive in the struggle for life with their less 

 anthropoid competitors.* It does not seem probable, to me at least, 

 that a naturally hairy species would entirely divest itself of its hair 

 through sexual selection, especially as the first steps of such a process 

 could hardly fail to render it a mongrel-looking and miserable crea- 

 ture ; but it seems natural enough that, if the original impulse was 

 given by a physical denudation, the influence of sexual selection would 

 rapidly strengthen and complete the process. Indeed, if a hairy animal 

 once began losing its hair, the only beauty which it could aim at would 

 be that of a smooth and shiny naked black skin. 



Woman is the sex most affected in mankind by sexual selection, as 



* On the advantages which man or his half-developed ancestor derived from the erect 

 or semi-erect position, see Darwin, " Descent of Man," p. 53. 



