COLOR ADAPTATIONS. 
m 
become breeders. In some of the young the color so 
advantageous would be intensified, and these in turn 
would become progenitors. Thus, in the course of 
time, little by little, the white hare would be devel¬ 
oped. Many other animals of the cold areas are much 
lighter in the winter season than in the summer. This, 
too, seems to be due to natural selection, and to be 
brought about in the same manner. 
The power to imitate surroundings in the color of 
coverings appears to be for the purpose of protection, 
and it is very common, especially among insects and 
birds. The lion can easily hide in the long yellow 
grasses of his habitat; the tiger finds concealment in 
the checkered shade of the jungle; the lark and 
grouse sit safely on their nests in the dry grass; the 
tree-frog is hard to distinguish from the bark on which 
he sits; and beetles and bugs sink so completely in 
foliage and flower that motion only betrays their 
position. 
This is an advantage in the struggle for life: 
those having the most perfect imitation find the best 
protection, and hence are fittest to survive. Thus 
they are selected to become parents of offspring, 
some of which are sure to intensify the protective 
quality. 
In some creatures the color is a warning to ene¬ 
mies, as, for instance, the Ileliconidse family of but- 
terfiies, which is more fully described in Book lY. 
In others color is for the purpose of recognition. 
A good example is the cottontail rabbit. The young 
can easily follow Molly’s white flag to a safe retreat. 
