BLUE-FOX FAEMIXG IN ALASKA 19 
Of the effective means at the command of the breeder to improve 
the stock, next in importance to selection is the judicious mating of 
related animals. This process is known as inbreeding. Inbreeding 
can be carried on successfully only where animals are kept in con- 
finement and their identity known. Following the method of grad- 
ing just described, however, and not introducing new and better 
males from other sources, would eventually result m inbreeding. 
TIME OF BREEDING 
Most blue-fox pups mate at the age of 10 months and produce 
young when they are about a year old. Apparently the breeding 
season varies slightly in different regions and at times is influenced 
by variation in the climate. The mating season, or, as it is com- 
monly known among ranchers, the w ' barking " period, starts about 
the first of February and continues for approximately 40 days. 
Most of the matings occur during February and March. 
So far as known, the oestrum, or heat period, occurs once a year 
and lasts 3 or 4 days. While the vixen will accept service only at 
this time, it seems to make little difference whether it is early or 
late in the period. 
The gestation period is 51 or 52 days and the young are usually 
whelped in April or May, although sometimes as late as the middle 
of June. Litters vary in number from 1 to 14, but the average 
number raised is about 5. 
MATING 
Improving the stock by selective breeding will undoubtedly result 
in increased profits in fox raising. If the more remote as well as 
the immediate ancestors have been bred with the aim of producing 
extra fine pelts, then the chances are that this will be transmitted to 
most of the offspring from such matings. 
In selecting blue foxes for breeders, it is to be borne in mind 
that pelts have a tendency to become lighter with age. Xo foxes 
showing white markings in the fur should be kept for breeding. 
Occasionally, however, a blue fox may show a white star on its 
breast, but this is not objectionable. 
The possibilities of modification or improvement by selective 
breeding are fully as great with foxes as with domesticated animals, 
and selective breeding will therefore in time produce a much finer 
strain of foxes. 
Ordinarily blue foxes have only one mate, but occasionally a male 
will have two, and there are a few reports of a male having three. 
ESSENTIALS OF FEEDING 
The real object to be kept in mind in feeding foxes is to supply 
nutritive material for building and repairing the body and for pro- 
ducing good fur. The ration must be wholesome and acceptable, 
and at the same time reasonably cheap. Cleanliness in preparation 
and regularity in feeding are important. 
While it is recognized that it is almost impossible to follow out 
ideal systems of feeding under present conditions on islands, yet it 
