Like dogs, [the researchers] say, ferrets originally were bred for practical reasons like hunting. Their role within human society has since shifted, as they now predominantly serve as pets. If ferrets adapted to a new social ecology within human society as have other domestic species, like dogs and horses, then they ought to respond to humans differently than their wild forebears.
So how did the ferrets do in a test?
The domestic species – ferrets and dogs – tolerated prolonged eye-contact from their owners, but not from strangers, while the wild mustelids [a mix of polecats, weasels, otters, badgers, minks] did not show this distinction. Ferrets and dogs were also both more likely to accept food from their owners than from strangers, while the wild mustelids made their approach decisions randomly, equally preferring their owners and a stranger (In fact, there was a slight but statistically insignificant preference for the stranger!)
(Photo by Flickr user downatthezoo)