Relating it to humans gets far more awkward than you might guess. Ponder any implications of what Wikipedia dares to say about the matter: The changes manifest

Relating it to humans gets far more awkward than you might guess. Ponder any implications of what Wikipedia dares to say about the matter: The changes manifested by the tame foxes over the generations, moreover, were not only behavioral but also physiological, just as Belyayev had expected. The first physiological change detected in the tame foxes was a lower adrenaline level. Belyayev and his team "theorized that adrenaline might share a biochemical pathway with melanin, which controls pigment production in fur", a hypothesis that has since been confirmed by research.[2] As they became tamer, more and more of the foxes began showing "signs of the domestication phenotype"; Trut later recalled that in the early 1980s "we observed a kind of explosion-like change of the external appearance."[5] After eight to ten generations, the tame foxes began to develop particolored coats, a trait found more in domesticated animals than in wild ones Belyayev's experimental animals and their descendants have been said to "form an unparalleled resource for studying the process and genetics of domestication".[1] Brian Hare, a biological anthropologist, wanted to study "the unusual ability of dogs to understand human gestures". Hare "wanted to know if dogs' powerful rapport with humans was a quality that the original domesticators of the dog had selected for, or whether it had just come along with the tameness, as implied by Belyaev's hypothesis". He discovered "that the fox kits from Belyaev's domesticated stock did just as well as puppies in picking up cues from people about hidden food, even though they had almost no previous experience with humans."[1] In a 2005 paper for Current Biology, Hare suggested that selection for tameness "may have been sufficient to produce the unusual ability of dogs to use human communicative gestures" and that the inability of wild wolves to pick up human cues is caused by their fear of humans. While Belyayev and his team "didn't select for a smarter fox but for a nice fox", Hare said, "they ended up getting a smart fox." Belyayev's research, Hare further argues, has implications for the origins of human social behavior: "Are we domesticated in the sense of dogs? No. But I am comfortable saying that the first thing that has to happen to get a human from an apelike ancestor is a substantial increase in tolerance toward one another. There had to be a change in our social system."[5]