Some domestic dog breeds have floppy ears, although the wolves they descended from do not. Charles Darwin puzzled over this as far back as 1869. But what's even weirder is that some domestic pigs, rabbits, goats, and cows have floppy ears, too, even though their wild counterparts do not. Does the act of domesticating animals make them relax their ears? It can't be that simple. And it's not.
Scientists believe it has to do with neural crest cells, which are explained in this video from Skunk Bear. You can read more about the Neural Crest Cell hypothesis here. -via The Kid Should See This