THE NORWEGIAN LEMMING AND ITS MIGRATIONS. 
149 
it was proved to be so, but because so little is known about it 
at all. The answer to the second question is certain : the} 7 go 
to the sea. Those on the east of the backbone of Norway go 
to the Gulf of Bothnia, and those on the west to the Atlantic 
Ocean (fig. 4), and out of 18 migrations which have been 
investigated, one only, and that very doubtful, is reported 
Fig. 4. 
0 b 10 1b W 15 
Outline map of Scandinavia. The two main valleys, G-udbrandsdalen, and the 
valley of the Glommen, run nearly north and south. The course of the Lem- 
mings crosses there at right angles, as indicated by the arrows. 
to have been directed southward. The question as to the 
cause of these migrations remains, and is a very difficult one 
to answer. We have been told that the foreknowledge of 
approaching severe weather predetermines the exodus : my 
experience, however, contradicts this, and it may be dismissed 
as merely a popular superstition. Unusual reproduction and 
