FLUCTUATIONS OF FUR-BEARING ANIMALS 223 
Red fox: 9, 10, 10, 10, 9, giving an average periodic cycle 
of 9.6 years. 
Cross fox: 9, 9, 10, 9, 10, giving an average periodic cycle 
of 9.4 years. 
Black fox: 10, 9, 10, 9, 10, giving an average periodic cycle 
of 9.6 years. 
By comparing these years with the years of maximum 
abundance of lynx and rabbit, it will be found that they 
coincide fairly closely. 
The white arctic fox and its colour phase the blue fox 
inhabit the northern Barren Grounds and the islands of the 
Arctic Sea in the summer. In the winter many of them 
wander southward in search of food. This species is re- 
ported to make caches of food for winter consumption. 
MacFarlane states that ‘‘Captain Lockwood found several 
fox lairs. In one hidden rock nook he found fifty dead 
lemmings, in others (sand and earth covered) there were 
from twenty to thirty lemmings, while in a hollow he dis- 
covered a cache containing part of a polar hare and the 
wings of a young brent goose and the usual lemming. The 
lairs appeared to be occupied from year to year.” 
The numbers appear to fluctuate very considerably over 
shorter periods than is the case with the more southerly 
red fox and its colour phases. ‘The Hudson’s Bay Company’s 
returns give the following years of maximum abundance: 
1856, 1861, 1864, 1869, 1873, 1878, 1884, 1888, 1892, 1896, 
1899, 1903, 1907, 1911. 
The periodic cycles accordingly covered the following num-~ 
ber of years: 
5, 3, 5, 4, 5, 6,.4, 4, 4, 3, 4, 4, 4. 
The average periodical cycle occurred in 4.2 years; 4 years 
was the actual length of the periodic cycle in the majority 
of the periods. 
