FLUCTUATIONS OF FUR-BEARING ANIMALS 225 
The periods of maximum abundance of the blue phase 
of the arctic fox correspond in almost every case with those 
of the white phase, so no special reference to these is neces- 
sary. / 
Wolves.—When the fluctuations in numbers of the larger 
predatory animals, such as the wolf, are studied it is found 
that they do not show a very regular or marked periodicity. 
This is no doubt accounted for by the wide range of their 
food, the grey wolf feeding on all forms of herbivorous 
animals, from a mouse to a moose, and the prairie wolf or 
coyote being a very general feeder, including in its diet not 
only larger animals such as antelope or sheep, but even in- 
sects such as locusts, and also berries. When mice or rab- 
bits are plentiful wolves will take their share of such abun- 
dant food, but the fact that they can also satisfy their 
hunger with deer, caribou, or moose prevents any marked 
decrease in their numbers when the smaller rodents are 
killed off. In fact, if we examine the diagrams of rabbit 
and wolf returns of the Hudson’s Bay Company (the wolf 
returns include both grey wolf and coyote) we shall find 
that in a number of instances the greatest number of wolves 
were taken in years of rabbit scarcity, and when rabbits 
were at their maximum the wolf returns were low. The 
greater difficulty of trapping wolves during periods of rab- 
- bit abundance may have something to do with this condition 
of affairs, but it is in striking contrast to the cases of the 
lesser carnivorous fur-bearers, the lynx and red foxes. In 
the early days when the buffalo roamed the prairies the 
wolves found food in plenty, and the returns from about 
1840 onwards until the buffalo began to decrease in num- 
bers showed no great increase or decrease. But when the 
buffalo was gradually exterminated the numbers of wolves 
fell to a low level, and since 1879 we find a slight, though 
nevertheless noticeable, periodical increase every ten years, 
the years of maximum abundance being 1888, 1898, and 1908. 
