22 COMMISSION OF CONSERVATION 
There is a wide-spread belief that the silver descend- 
Rearing Silver ants of red foxes are rusty black in colour and are 
Foxes from Reds : 
not as pure a type as those bred pure for generations 
in the foxranches. Professor W. E. Castle, of Harvard University, says 
that only experiments will prove what quality will be obtained in the 
silver young of a red parent.* The results noted in this investigation 
indicate that some of the best skins ever produced are those of silvers 
having ared parent. There was difficulty in obtaining information on 
this important point as breeders were extremely reticent in giving in- 
formation concerning their experiences in cross-breeding with reds, 
because of a great prejudice against such breeding on Prince Edward 
Island. The prejudice, no doubt, results from an ignorance of Mendel- 
ian principles in segregating types. 
It is interesting to note that Rev. George Clark, of St. Catharines, 
Ont., has in his possession a black dog fox obtained from near York 
Factory, Hudson Bay, which, he asserts, has sired none but silver pups, 
when mated with any vixen. Of course, the five or six litters sired by 
one dog does not provide sufficient data from which to form a general 
conclusion. It may be that many of the thousand or more red foxes kept 
in captivity will yet be crossed so as to produce a proportion of silver 
stock. As the red foxes were generally purchased from districts which 
produce very ordinary pelts, it is quite probable that, in many cases, the 
resulting silver will not be of good quality. The climatic conditions of 
Canada, however, which are very favourable to the production of good 
pelts, may improve exotic sub-species. 
Breeders are generally better pleased if cross foxes are 
Cross Foxes = produced the first generation; but, as a rule, if cross foxes 
as Breeders i 
are bred out, the tendency to produce an occasional red 
pup will never be wholly eliminated. Having cross foxes in the ancestry 
of silver foxes means that a proportion of red gametes are thrown and 
* Professor Castle, replying to an inquiry, says: 
“The several facts stated in your letter of November 14th, which I assume 
you have sufficiently verified, show clearly that black (or silver) coat character 
in foxes is a Mendelian recessive in relation to the common red coat and may be 
recovered in the second generation from a cross with red. Whether it would be 
improved or deteriorated as a consequence, experiment alone could show. I should 
think that the ‘patch’ or ‘cross’ foxes occasionally obtained in the F, generation 
might be well worth experimenting with, as indicating in that particular strain a 
tendency for the dominance to be reversed. If this tendency could be strengthened 
by judicious selection, a more potent strain of silvers might result. If, by this 
means, a strain potent enough to dominate F', could be secured, it is evident that 
silver foxes could be produced much more readily.” 
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