THE ALLIES OF THE SQUIRREL 425 



and that they are not prone to defend themselves except 

 under great provocation. The presence of this means of 

 defense has had its effect upon the skunk's character, so 

 that if a person comes upon it in the daytime it is 

 likely to make no special effort to escape, but goes about 

 its business leisurely, secure in the confidence that it will 

 not be molested. The Eastern species are black animals 

 about the size of a cat, with prominent white stripes down 

 the back and a white patch on the forehead. The white 

 markings on the black ground are usually cited as an ex- 

 ample of warning coloration. It has been asserted that it is 

 advantageous to the skunk to be thus marked, for if it had 

 a uniform black color, it might be mistaken in the uncertain 

 light for other night prowlers and be pounced upon and 

 killed by an enemy before it had an opportunity to use its 

 peculiar method of defense. 



Among the aquatic carnivorous forms the Alaskan fur 

 seal (Callota'ria alasca'nus) has been the subject of inter- 

 national discussion on account of the value of its fur as an 

 article of commerce. This is a truly migratory species of 

 mammal, bringing up its young on the Pribilof, or Fur Seal, 

 Islands (Fig. 223) in the summer, and going far to sea in the 

 winter. The males do not reach their full size and strength 

 till about the seventh year, and until that age the young 

 males herd by themselves, being forbidden the general herd 

 by the older males. The females mature in two years. 

 Early in May the full-grown males appear at the islands, 

 and the females a few weeks afterward. Each male im- 

 mediately collects as many females as he can guard, and 

 battles are frequent before the groups are made up. From 

 twenty to one hundred females, or "cow" seals, are included 

 in a single harem. 



The government-owned seal herd in the Pribilof Islands 

 is the world's chief supply of sealskin. This herd now totals 



