Interesting - when I happened to come across it in a book or on TV I always knew what it meant, but never thought about the origins.

That's a good one! Never would have thought that but totally makes sense.

Could be when the word was taken into English, we mispronounced it. Or maybe it was from a language other than German. Still sounds like an Old Country last name to me. eta: Okay I caved and looked it up. The origin probably came through the Old English, German, or Yiddish word for "chest", spellings (and opinions) vary.

Lots of creatures will get their back up when confronted ... Sort of like when the hairs on the back of your neck stand up.