THE TUNDRA AND ITS FAUNA 23 
polar, but does not extend so far to the north as the 
other species. 
In the tundra, as elsewhere, the presence of large 
herbivores naturally attracts their enemies the large 
carnivores, necessarily fewer in number, and usually of 
greater intelligence. As masterful and highly organized 
animals the large carnivores do not as a rule show 
a very close adaptation to one type of country only, 
nor are they, as a rule, like such herbivorous animals 
as the musk-ox, driven by stress of competition to the 
unfavourable parts of the surface. The carnivores 
which occur in the tundra, therefore, do not as a rule 
form an integral part of its fauna; rather are they 
intruders from other regions. Thus the wolf (Canis 
lupus), absent in Greenland, in Spitsbergen, &c., occurs 
in Arctic Asia and Arctic America, and extends also 
into such regions as Grinnell Land and King Oscar 
Land. Its near ally, the Eskimo dog, is a very impor- 
tant animal in Greenland and elsewhere. Very in- 
sufficiently fed by its master, the catholicity of its 
appetite may be gathered from the fact that it will eat 
fish, shell-fish, seaweed, and refuse. 
Much more truly Arctic than the wolf is the Arctic 
fox (Canis lagopus), widely distributed in the polar 
regions of both the Old and New Worlds. Its food con- 
sists of birds, especially the ptarmigan, but it is con- 
strained to add to this refuse and even seaweed. 
Lemmings are also an important part of its diet where 
they occur, and by some it is believed to store the 
bodies of these for the winter, when it is often hard- 
pressed. Two other land carnivores occur in the tundra, 
but both are immigrants from their natural home 
further south. These are the ermine (Mustela erminea), 
which follows the lemming to the coasts of the Arctic 
