24 THE TUNDRA AND ITS FAUNA 



sea, and the glutton {Gulo luscus), a forest mammal, 

 which just reaches the tundra. 



Among the mammals which find their food in the sea, 

 we must place the polar bear. As its name ( Ursus mari- 

 timus) indicates, this animal haunts the margin of the 

 sea, where it is found among the drift and floe ice, on 

 the look out for its natural prey, seals and the walrus. 

 It is thus not in any true sense a tundra animal, al-, 

 though occurring round the margin of the tundra region 

 throughout its extension. Of the many kinds of seals 

 also, we can only say here that though they breed on 

 the shore they are not in any sense tundra animals. 



We may pass next to the birds of the tundra. In 

 regard to these it is noticeable that large numbers of 

 migrants occur, especially sea birds and those which 

 haunt the vicinity of the shore or of fresh water. 

 These come north to breed in the relative security of 

 the tundra; and also probably because they find the 

 long northern daylight an advantage, for it lengthens 

 the period during which the search for food can be 

 carried on. As winter approaches, these birds travel 

 southwards, fleeing from the increasing cold and dark- 

 ness. It is unnecessary to give lists of these migratory 

 forms. All travellers to tundra regions, whether to the 

 mainland areas or to the lands of the polar sea, speak 

 of many kinds of gulls, of skuas, of kittiwakes, of 

 geese, of various forms of ducks, including the eider, of 

 auks and guillemots, of sandpipers, terns, petrels, and 

 so forth, none of which can be regarded as definitely 

 characteristic of the tundra, though their summer 

 abundance at certain special locahties is one of the 

 features of the region. It is otherwise with the true 

 land birds, which, though relatively few in number, 

 help to give its characteristic facies to the region. First 



