improve their weapons.
But in very many cases the males which conquer their rivals, do not
obtain possession of the females, independently of the choice of the
latter. The courtship of animals is by no means so simple and short an
affair as might be thought. The females are most excited by, or prefer
pairing with, the more ornamented males, or those which are the best
songsters, or play the best antics; but it is obviously probable that
they would at the same time prefer the more vigorous and lively males,
and this has in some cases been confirmed by actual observation. (9.
With respect to poultry, I have received information, hereafter to be
given, to this effect. Even with birds, such as pigeons, which pair for
life, the female, as I hear from Mr. Jenner Weir, will desert her mate
if he is injured or grows weak.) Thus the more vigorous females, which
are the first to breed, will have the choice of many males; and though
they may not always select the strongest or best armed, they will
select those which are vigorous and well armed, and in other respects
the most attractive. Both sexes, therefore, of such early pairs would
as above explained, have an advantage over others in rearing offspring;
and this apparently has sufficed during a long course of generations to
add not only to the strength and fighting powers of the males, but
likewise to their various ornaments or other attractions.
In the converse and much rarer case of the males selecting particular
females, it is plain that those which were the most vigorous and had
conquered others, would have the freest choice; and it is almost
certain that they would select vigorous as well as attractive females.
Such pairs would have an advantage in rearing offspring, more
especially if the male had the power to defend the female during the
pairing-season as occurs with some of the higher animals, or aided her
in providing for the young. The same principles would apply if each sex
preferred and selected certain individuals of the opposite sex;
supposing that they selected not only the more attractive, but likewise
the more vigorous individuals.
NUMERICAL PROPORTION OF THE TWO SEXES.
I have remarked that sexual selection would be a simple affair if the
males were considerably more numerous than the females. Hence I was led
to investigate, as far as I could, the proportions between the two
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