100 THE MEANING OF EVOLUTION 
birds lies somewhere between one hundred and five de- 
grees and a hundred and ten. Creatures which are 
warmer than their surroundings must have some pro- 
tection against chilling. Accordingly both mammals 
and birds have clothing. In the case of mammals 
the covering is fur, in the case of birds feathers. In 
some of the tropical animals like the elephant and 
rhinoceros, or in man, who has learned to protect him- 
self in cold regions by making clothing for himself, 
this hair is very short, and except where serving for 
ornament is quite scanty, no longer being of use as a 
protection. But the great majority of all mammals 
are well covered with a dense coat of hair. In many 
of those living in the colder regions there is in reality 
a double coat. The fur seal of the Alaskan Islands is 
so provided. ‘A set of long hairs deeply fastened in 
the skin forms a covering, which shows on looking 
at the seal. Underneath this layer, and set but lightly 
into the skin, is a short coat of very much finer hair 
known as the underpelt. When the skin is taken from 
the seal it is split by machinery into a lower and an up- 
per layer. When so split the deep-seated pits of the 
long hairs are cut, and these hairs come out. The fine 
underpelt thus laid bare is what is commonly known 
as sealskin. Fashion has decreed that this must be 
dyed a rich brown, although when taken from the 
animal it is nearly mouse gray. 
