In the 1950s, a group of scientists in Russia launched an experiment to domesticate foxes. They had some success, breeding domesticated animals within 10 generations. They judged the foxes’ level of domestication by their temperament when interacting with humans, including how aggressive they were and how much they tried to avoid human contact.
The foxes that were the tamest were bred to each other, and future generations of foxes ended up quite receptive to human affection and company. During the process, some were born with spotted coats, curly tails and floppy ears as well as different balances of testosterone and adrenalin than wild foxes. Basically, they became more dog-like.
However, the program is no longer funded because domesticated foxes were still very difficult to keep as pets.