216 CONSERVATION OF CANADIAN WILD LIFE 
practically uninfluenced by the agricultural development of 
the country, their returns may be taken, not only as an in- 
dex of the total quantity of furs of the different species of 
fur-bearing animals taken in Canada in any year, but also 
as a fair index of the relative abundance of these species. 
From these figures the accompanying charts have been pre- 
pared, and they illustrate very graphically the abundance 
from year to year of the chief species of fur-bearers and their 
periodic increase and decrease.* 
Varying Hare or Rabbit.—If we study the data respecting 
the increase and decrease in abundance of the common rab- 
bit or varying hare (Lepus americanus), which is widely dis- 
tributed throughout the country, especially in the north, 
we find ample confirmation of the well-known facts respect- 
ing the abundance from year to year of this common food 
and fur-bearing animal. Their capacity for increase in 
numbers is very great. 
The females usually begin to breed when a year old. 
They bear two or three, and sometimes four to six young 
at a time, and are said to breed two or three times in a 
season, the period of gestation being about thirty days. 
MacFarlane states: ‘‘The litter usually consists of three or 
four; but when in the ‘periodic’ increase, females are known 
to have as many as six, eight, or even ten at a time, and 
then gradually return to three or four.” 
If we take the periods of maximum abundance of the rab- 
bit, according to the Hudson’s Bay Company’s returns, we 
find they occurred in the following years: 
1845, 1854, 1857, 1865, 1877, 1888, 1897, and 1905, or in 
other words in cycles of 9, 3, 8, 12, 11, 9, and 8, 
giving an average periodic cycle of 8.5 years. 
* MacFarlane, in his ‘‘Mammals of the Northwest Territories’ (1905), a 
memoir to which I make frequent reference, and E. T. Seton, in his book 
“The Arctic Prairies,” have called attention to these fur returns and the 
indications they afford of the fluctuations in number of the fur-bearing animals. 
