THE WAY OF THE WILD 65 
the most inconspicuous color. For example, the white color of 
the albino deer, shown on page 102, would be against him, as it 
would be in favor of the polar bear with his different surround- 
ings. It means the bird or beast most successful in hiding or 
in eluding its pursuers, and everything which helps in this will 
help to make the “fit’’ more perfect and thereby to more 
certainly insure survival. 
With plants it means the fastest-growing stem which will 
most certainly reach the sun, or the deepest-running root which 
alone will secure moisture in time of drought ; it means the most 
spiny covering which protects best against herbivorous animals, 
the most showy flowers or the most penetrating odors which best 
assure fertilization, or the most toothsome and conspicuous seeds 
which best attract bird or squirrel to carry off and bury, some 
portion of which is never recovered. These are the circum- 
stances that determine the fitness to survive. 
On careful study it will be seen that every species has some 
natural trait or character, which, in a state of nature, enabled 
it to survive, else it would not be here now; and of this 
species the individuals that possess this character in the great- 
est perfection are the ones that best withstand the rigors of 
natural selection. Species and individuals not possessing such 
natural advantages at once become extinct, as do those whose 
advantage is rendered worthless by some sudden change in 
the surroundings. 
For example, the natural advantage of the birds generally is 
their aérial flight and their powers of rapid reproduction ; with 
the yellow butterfly it is his offensive taste ; with the caterpillar 
it is his hairy covering, which, like the spines of the porcupine, 
are unpleasant to the attacking party; with the cat tribe it is 
the prehensible claw and the silent tread; with the antelope it 
is his wonderful scent and his fleetness ; with the pig it is his 
long snout with its remarkable rooter ; with the elephant it is 
his trunk; with the beaver it is his tooth and his tail; with the 
snake it is his venom and his incurving teeth ; with the sheep, 
