NATURAL SELECTION 231 
ing around, like Indians in a war-dance, for the possession of the 
females; male salmons 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 insects have been fre- 
quently seen by that inimitable observer M. Fabre, fighting for a 
particular female who sits by, an apparently unconcerned beholder 
of the struggle, and then retires with the conqueror. The war is, 
perhaps, severest between the males of polygamous animals, and 
these seem oftenest provided with special weapons. The males of 
carnivorous animals are already well armed; though to them and to 
others, special means of defense may be given through means of 
sexual selection, as the mane of the lion, and the hooked jaw to the 
male salmon; for the shield may be as important for victory as the 
sword or spear. 
Amongst birds, the contest is often of a more peaceful character. 
All those who have attended to the subject believe that there is the 
severest rivalry between the males of many species to attract, by 
singing, the females. The rock-thrush of Guiana, birds of paradise, 
and some others, congregate; and successive males display with the 
most elaborate care, and show off in the best manner, their gorgeous 
plumage; they likewise perform strange antics before the females, 
which, standing by as spectators, at last choose the most attractive 
partner. Those who have closely attended to birds in confinement 
well know that they often take individual preferences and dislikes: 
thus Sir R. Heron has described how a pied peacock was eminently 
attractive to all his hen birds. I cannot here enter on the necessary 
details; but if man can in a short time give beauty and an elegant 
carriage to his bantams, according to his standard of beauty, I can 
see no good reason to doubt that female birds, by selecting, during 
thousands of generations, the most melodious or beautiful males, 
according to their standard of beauty, might produce a marked effect. 
Some well-known laws, with respect to the plumage of male and 
female birds, in comparison with the plumage of the young, can partly 
be explained through the action of sexual selection on variations 
occurring at different ages, and transmitted to the males alone or to 
both sexes at corresponding ages; but I have not space here to enter 
on this subject. 
Thus.it is, as I believe, that when the males and females of any 
animal have the same general habits of life, but differ in structure, 
color, or ornament, such differences have been mainly caused by sexual 
