Yup, that's another stereotype JKR hits. I ought to have seen that, being fat myself and subject to the usual social prejudices against fat people.
"..boys of that age rarely seem capable of fathoming the idea that something besides themselves might have feelings" ~ you hit that nail on the head! It's consistent with school kids, especially school boys. But I would love to see one scene where McGonagall or Hagrid, or someone, takes those experimental animals, fixes them back to normal, wipes the memory of the pain, and returns them safely to their natural habitat.
Hey! What's the matter with being a dog?!? Dogs are great. (I have 5 dogs, too...) And Sirius was such a cool dog, big and black and ominous.
Sorry if you already addressed the issue ~ I probably forgot. My memory isn't the greatest. I've never heard of Katharine Kerr ~ is she good?