THE TUNDRA AND ITS FAUNA 21 
character of the tundra animals, like the fewer animals 
of the Antarctic area, that it is marine plants, rather 
than terrestrial ones, which form the basis of their 
food supply. 
Having thus summarized the conditions of life in the 
tundra we may give some account of the fauna, begin- 
ning with the ungulates among mammals. The rein- 
deer (Rangifer tarandus) is widely spread throughout 
the region, though nowhere very abundant as indi- 
viduals. On the continent of America there is a marked 
distinction between those forms which haunt the forests, 
the so-called woodland caribou, and the smaller forms, 
with larger antlers, which occur in the tundra. The 
latter, the barren-ground forms, seem to migrate south- 
wards towards the forest in winter, but this is impossible 
with the herds which occur in the Arctic islands. In 
King Oscar Land and the adjacent regions the Sverdrup 
expedition found the animal widely distributed but not 
abundant, apparently on account of persecution by the 
Arctic wolf. The absence of this animal in Spits- 
bergen perhaps accounts for the greater abundance of 
the reindeer there. It occurs also in the suitable parts 
of Greenland, where the wolf is again absent. On the 
continent of Asia the reindeer occurs in summer in 
suitable localities in the tundra region, but here also it 
seems migratory, and thus not wholly dependent upon 
the tundra for food. 
The musk-ox (Ovibos moschatus), the second large 
herbivore of polar regions, has a much more limited 
distribution. Found fossil in Europe and Asia, it is 
now limited to the American side of Arctic regions. 
On the continent of America its eastward distribution 
is limited by the Mackenzie River, but it is apparently 
abundant in the northern parts of Greenland, in 
