70 CHILDHOOD OF ANIMALS 



habits, as in the case of pigeons, partridges, most parrots, owls, 

 birds-of-prey, and many of the small singing birds. There are even 

 a few odd cases where there is a conspicuous difference in colora- 

 tion and the females are the more resplendent. This happens in 

 phalaropes, some button-quails, painted snipes and cassowaries, and 

 it is curious that in these cases the usual disposition of the sexes 

 is reversed, and the females are pugnacious, aggressive and courtiers 

 of the males. The sexes are usually alike in reptiles, but male 

 lizards may be brightly coloured when the breeding season 

 approaches. Amongst batrachians there are many in which the 

 sexes are alike, but male newts assume a brilliant nuptial colora- 

 tion. Whilst the males and females of most fishes are alike in 

 colour, there are many well-known examples of males becoming 

 more brilliant in the breeding season. Butterflies, moths, beetles 

 and bugs, and dragon-flies may be clad in sober or gaudy tints, and 

 are frequently alike in the two sexes, but where there is a difference 

 it is almost invariably the male sex that is conspicuous. In spiders, 

 again, the males are not infrequently more brightly coloured than 

 their mates. The interpretation of such sexual coloration is very 

 difficult. In some cases, especially those of insects where the 

 sexes are alike, bright colours belong to some other category of 

 coloration, or, as Darwin suggested, may have been acquired in 

 one sex and then transmitted by inheritance to both sexes. In 

 other cases they may be the mere expression of exuberant vitality, 

 of active physiological processes, and may be of no special utility 

 so far as the attraction of the sexes is concerned, but may have 

 been retained in the brilliantly coloured males because their presence 

 was not disadvantageous, and suppressed in the dull females where 

 it was of advantage to the next generation that the female should 

 be inconspicuous during her laying of the eggs and guardianship of 

 the young. But there remain a large number of cases where one 

 sex, almost invariably the male, is always conspicuous during the 

 breeding season, whether that occupy the whole adult life or be a 

 recurrent episode. In such cases it certainly seems to be an advan- 

 tage to the male to be conspicuous, and there is no better interpreta- 

 tion of these facts than that given more than forty years ago, with 

 the most judicial reticence, by Charles Darwin in the " Descent of 

 Man and Selection in Relation to Sex." Darwin showed that 

 in very many cases where the males were conspicuously coloured, 

 they flaunted their colours and patterns before the female, excited 

 her attention by them, and gave her the opportunity, consciously 



