36 PREHISTORIC EUROPE. 



morass are frozen — and hardly a trace of animal life is to be 

 seen. But soon after trie return of spring, when the ground 

 begins to thaw and the snow to vanish, lichens and herbs and 

 grasses reappear, and the summer heat by and by becomes 

 almost as intolerable as the winter cold. The tundras are now 

 enlivened by the presence of great herds of reindeer and other 

 animals, and by vast nights of wild birds which find a plentiful 

 harvest of food in the waters of river and lake and sea. 



Thus, owing to the strongly-contrasted conditions of summer 

 and winter in these Arctic regions, both birds and beasts are 

 compelled to perform great migrations. In winter the reindeer 

 seek the shelter of the woods, where they trespass upon the 

 territory of the elk or moose-deer, and in which they frequently 

 fall a prey to wolves and bears. As soon, however, as the 

 milder weather begins, they return in large bands to the tundras 

 and barrens, feeding on the lichens that are softened by the 

 melting snow. 



The area over which the reindeer-migrations take place is 

 vastly more extensive in America and Asia than in Europe, its 

 southern limits corresponding very nearly to the isothermal of 

 32°. No doubt this area extended farther south in Norway 

 within recent years ; but even were the disturbing influence of 

 man to be entirely withdrawn, we cannot believe that under 

 present climatic conditions the reindeer would ever reach in 

 Western Europe the same low latitudes that it now attains in 

 Asia and America, for it ranges into Kamtschatka as far south 

 as the parallel of 50° N. lat., which it will be remembered 

 passes through the north of France. 



The climatic conditions that induce great migrations, like 

 those of the northern regions of Asia and North America, do 

 not obtain in the corresponding territories of North-western 

 Europe. Our prevalent winds are westerly and south-westerly, 

 and come to us laden with the warmth and moisture of the Gulf 

 Stream, and thus, as I have said, we enjoy a kind of insular 

 climate, with no great extremes of heat and cold. Such being 

 the case, and it being perfectly well ascertained that during 



