Did you ever wonder why Pluto is Mickey's dog, but Goofy, who's also a dog, is on a more or less equal footing? (This what you get when I wake up with insomnia.) When I was a kid, this used to bug the hell out of me. I count it as one of the triumphs of my life that I was eventually able to learn the answer straight from the mouse's mouth, as it were. Once I was working for Disney animation I had to climb a surprisingly long way up the chain of command to find out; eventually Jeffrey Katzenberg himself told me. And, as is the case with most things Disney, there's a certain twisted logic to it.
It seems that, among the various sentient beings of the Disneyverse, (by which I mean those created by the studio, not purchased as outside properties such as Baloo the Bear or Winnie-the-Pooh -- who's also a bear, come to think [I prefer to read into this merely the fact that I'm typing this at 6 AM]), anyway, among the inhabitants of Duckburg (and before you ask, I have no fucking idea if Mickey lives in Duckburg or the neighboring hamlet of Mouseville [which I believe I just made up]. For all I know, he lives in Secaucus), so anyway, the way it works is simply thus:
It doesn't matter what kind of animal you are in a Disney cartoon; if you are bipedal, can talk and wear clothes, then PETA be damned; you can own "lower" animals and do with them as you will.
This answers a lot of questions. Goofy, for instance, is nominally a dog. But he's bipedal (albeit with horrendous posture), wears clothes (sort of; interestingly, he's one of the few inhabitants whose ensemble includes pants), and speaks a colorful patois of English. All of which evidence his canine antecedents while simultaneously showcasing his cultural and evolutionary superiority over Pluto, who's also a dog, but who goes on all fours and wears naught but a dog collar (and to all those with fingers poised gleefully over their keyboards who live in West Hollywood, the Castro District, or other places like them -- you're only muddying the waters; shut up).
As I said, this clears up a lot of questions. But it also opened -- for me, anyway -- a veritable Matryoshka of Pandora's boxes. None of which I intend to go into now, save to note that I'm still not at peace -- and most likely never will be -- with the horror I felt as a seven-year old when I opened an Uncle Scrooge comic and witnessed the entire McDuck clan -- Scrooge, Donald, Daisy, and the trifecta of nephews -- sitting down with drooling beaks, utensils firmly gripped in feathered fists, and napkins knotted around wattled necks, to a turkey dinner with all the trimmings.