Why do some many of our domesticated animals have floppy ears and spots? Have you ever stopped to wonder why you almost never see these traits in wild animals yet if you look at domesticated cats, dogs, rabbits, guinea pigs, horses, cows, and pigs they are very common?
It turns out that these are some of the physical changes that are brought out when animals are selected for domestication in any species. Not only that, but in two or three generations animals can radically change their physical traits and appearance when humans select in this way.
Here is a fascinating article, Clever as a fox, on the domestication of animals and the Dmitri Belyaev fox experiments on domestication.