CHAPTER I 
THE TUNDRA AND ITS FAUNA 
One of the well-marked natural regions of the world 
is the Tundra, that treeless area which fringes the 
margin of the far northern seas, and is characterized 
by its climate, its plants and animals, and to some 
extent also by its topography. Originally applied only 
_to the treeless lands of Northern Asia, lying to the 
north of the forest or taiga, the term is now by exten- 
sion given to all areas of similar character, occurring 
alike in the Old and New Worlds. In the southern 
hemisphere the tapering of the land-masses, and their 
cessation in relatively low latitudes, make the develop- 
ment of true tundra impossible. It is true that con- 
siderable land-masses occur within the Antarctic area, in 
latitudes lower than those in which the northern tundra 
finds its limit, but the climate and the absence of a direct 
connexion between these areas and the continents have 
prevented the development of the characteristic tundra 
plants and animals. In the Antarctic land-mass flower- 
ing plants are, with two exceptions, absent, and mosses 
and lichens are only slightly developed. Associated 
with this we have a complete absence of land mammals 
—a very striking difference from the northern tundra. 
The boundaries of the tundra are well marked. As 
already indicated, on the continents the southern 
boundary is the beginning of the forest zone. ‘This 
limit is, roughly speaking, marked out by the July 
isotherm of 50°. Wherever the mean temperature of 
the hottest month exceeds 50° F., there the tundra 
