How were researchers belyaev and trot able to produce domesticated foxes?

Belyaev and Trot were well-known researchers who worked together to produce domesticated foxes. It began when Belyaev got 30 males and 100 females (vixens) from a commercial fur farm. This was important since these foxes were already tamer than wild ones since they had been subject to human contact and raised in the commercial fur farm. The foxes were placed in individual cages, had minimal contact with humans and were never trained. After a female gave birth, the babies would stay with her until they reached 3 months, and then placed in individual cages. Then the tests began to determine the tameness of the foxes. The person conducting the experiment would hand feed the foxes from when they were 1 month old until they were 6 months old. The foxes would also be petted and stroked during the feeding time. When the foxes were 7 months old, and able to breed they were put into these three classes; most domesticated, somewhat domesticated, and least domesticated. The foxes were being bred for this experiment for more than 40 years. Over time, the foxes became eager for human contact, they would even whimper for attention, and sniff and lick humans just as a dog would do. These foxes developed different coats and also critical sensory developments mush faster than a wild fox could. The foxes that were raised like this around humans also opened their eyes earlier, and over time their skull changed into a more feminine skull. They started the experiment because Belyaev noticed how over time domesticated dogs and other animals had changed over the years such as their hair being curly, tails were shorter, etc. In 2010, there were approximately 45,000 offspring from the original foxes he had taken from the commercial fur farm. In that year, 100 of the foxes are eager to please, docile, unmistakenly docile, and eager to please humans. 

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