It’s no secret that the foxes weren’t truly “wild,” Karlsson says. The Soviet foxes originally came from fur farms on Prince Edward Island in Canada, with selective breeding dating back to at least the 1880s. One of Karlsson’s colleagues, on vacation on the island, stumbled across fur farm photographs from the 1920s during a visit to a local museum. Those foxes appeared tame with spotted coats — one of the same domestication traits claimed as a by-product of the Russian experiment that supposedly took generations to emerge.

https://www.sciencenews.org/article/russian-foxes-tameness-domestication