Q:Explain the Corwin talking bear thing? It's been a long time since I read the five books, but I don't recall talking animals.
As rightly you shouldn’t. The Corwin talking bear thing was (and still is) an in-joke on the Amber mailing list. I was actually there when it started, believe it or not, round about 2000 or 2001; here’s a succinct summation.
It’s basically an old in-jokey shorthand for pointing out problems with an unreliable-narrator argument. “The text never directly states that this is NOT so… wait, maybe it does, but maybe they were lying…” …and Corwin is a talking bear, because it is never directly stated that he is not a talking bear, so pffft, that’s your argument.
For a while there was a cutely outrageous trend of pointing out places in the text that could be interpreted as such. “…and he’s hairy because he’s a talking bear!”