Silver (Siberian)

Fox

The Silver Fox is a melanistic form of red fox. Silver foxes display a great deal of pelt variation: some are completely black, save for the white tail tip, while others are bluish-grey, and others may have a cinereous colour on the sides. Historically, silver foxes were among the most valued furbearers, and their skins were frequently worn by nobles in Russia and other parts of Europe, as well as in China. Wild silver foxes do not reproduce exclusively with members of the same coat morph, and can be littermates with the common red variety, though captive populations bred for their fur are almost exclusively mated with members of the same colour.

http://en.wikipedia.org/wiki/Silver_fox_(animal)