THE WHITE WINTER COAT 



The whiteness of hair or feathers is due partly to 

 the absence of the usual pigment, and partly to the 

 presence of minute gas bubbles in the cells. The 

 whiteness of grey hair is thus in a way like the white- 

 ness of foam. 



There appear to be various advantages in a white 

 dress in very cold snowy regions. For a hot- 

 blooded animal, with a temperature high above 

 that of the surrounding world, the loss of heat is 

 less with white hairs or white feathers than with 

 any other colour of dress. This is probably the 

 chief advantage of turning white in winter, but it 

 must also be admitted that a white dress is the least 

 conspicuous dress in snowy regions as well as the 

 most comfortable. 



Where the struggle for existence is keen, it may 

 be but a little thing that decides whether the 

 creature is to survive or to be weeded out. Pro- 

 fessor Davenport had 300 chickens in a field, 80 per 

 cent, white or black and conspicuous, 20 per cent, 

 spotted and inconspicuous. In a short time twenty- 

 four were lulled by crows, but only one of the killed 

 was spotted. In this case the quality of whiteness 

 was disadvantageous, but in the north or among the 

 mountains those animals that turn white in winter are 

 likely to have their chances of life improved. 



No better example of a victorious creature could be 

 given than the snowy owl, a native of the barren 

 grounds of the Far North. It is a big bird, about 

 two feet in length, of white plumage with variable 

 dark spots and bars ; it has a strong and easy 

 flight, and hunts by day, picking up snow-birds 



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