ADAPTATIONS 137 
of his bright feathers. The female consents to be chosen 
by the one which pleases her. It is ‘believed that the hand- 
somest, most vivacious, and most musical males are the 
ones most successful in such courtship. With polygamous 
animals there is intense rivalry among the males in the 
mating season, which in almost all species is in the spring. 
The strongest males survive and reproduce their strength. 
The most notable adaptation is seen in the superior size 
of teeth, horns, mane, or spurs. Among the polygamous 
fur seals (Fig. '71) and sea lions the male is about four times 
Fie. 72,—A wild duck (Aythya) family. Male, female, and precocial young. 
the size of the female. In the polygamous family of deer, 
buffalo, and the domestic cattle and sheep, the male is larger 
and more powerfully armed than the female. In the polyg- 
amous group to which the hen, turkey, and peacock belong 
the males possess the display of plumage, and the structures 
adapted for fighting, with the will to use them. 
79. Adaptations for the defense of the young.—The pro- 
tection of the young is the source of many adaptive struc- 
tures as well as of the instincts by which such structures are 
