A domestic silver fox is a canid developed via a genetics experiment originally funded by the Soviet Union. The program began in 1959 and utilized a silvery gray color variant of the wild red fox, Vulpes vulpes. The experiment succeeded in producing a strain of tame foxes.
The domesticated foxes also began to display different physical traits from their wild cousins, namely, curled tails, floppier ears and new coat patterns. The aim of the experiment was to discover any links between behavior, breeding and domestication. The leader of the experiment, Dmitry K. Belyaev, used foxes from fox farms and selectively bred them for gentle behavior in his Siberia facility. Along with the domestication experiment, another experiment to breed more aggressive foxes was performed. The two breeding programs and crosses between the two strains established a genetic basis for tame or aggressive behavior.