6 THE ANIMALS OF ARCTIC ASIA 



The most abundant rodent of the tundra is the common lemming 



Lemming, ( j Lemmus norveygicus), whose distributional area extends from 



Norway through Siberia, and whose place is taken by other species in North 



America. Lemmings have very small ears, a rather stout body, an arched and 



rounded head, an extremely short tail, long claws, and thick fur; the different 



3 peciea varying to some degree in size and coloration. About 5 inches is the 



length of the common Norwegian species. This kind hibernates in winter and 



does not turn white. The Arctic lemming (Dicrostonyx torquatus), which under- 



„ > 8uch a colour-change, is remarkable for the fact of its developing two claws 



„.], front-toe with the assumption of the winter dress, the additional claw 



being used for digging. Lemmings subsist on grass, reindeer-moss, birch-catkins, 



and probably roots; but in seasons of scarcity they migrate in enormous numbers 



to other districts. If a mild winter be followed by an early spring and warm 



summer, lemmings increase rapidly, but the dry summer diminishes their food 





NORWEGIAN LEMMTNG. 



Btore, and thus induces them to travel long distances in search of a fresh supply. 

 V | only do these tiny rodents cross mountains, valleys, rivers, and lakes, but 

 Bometimea tiny fall in such numbers into wells and rivers that all the water in the 

 country i- contaminated and undrinkable. 



Swans. 



The Boreal /one is far richer in birds than in mammals, among 



its larger feathered inhabitants two kinds of swan being common on 



the tundra of the Siberian area. Of these, the whistling or whooper swan (Gygnus 



bul little known in Europe, although it regularly crosses the North 



md Baltic on migration. This species is abundant in the bays of Rugen and 



1 loin bul appears on the Frische Baffin such numbers as to make the meadows 



* > 1 1 its journeys it passes through England as well as northern 



Germany, and is seen as far south as the Lake of Constance and the Swiss lakes, 



and sometimes even crosses into northern Africa. Most whistling swans winter, 



lowever, in south-eastern Europe, and thousands have been seen at Varna on the 



Sea as well as in Asia Minor. Those wintering in Europe and Africa mostly 



