Later genomic mapping has revealed that forty genes now differ between Belyaev’s tame foxes and the wild silver fox. Incredibly, by selecting for one behavioral trait, the genome of the animal was changed in a half century. And with that genetic change came a number of surprisingly familiar physical changes: some of the later-generation foxes have multicolored, piebald coats, recognizable in dog mutts everywhere. They have floppy ears and tails that curl up and over their backs. Their heads are wider and their snouts are shorter. They are improbably cute.

