Check out You and Me Baby Ain't Nothing But Mammals and A Morphic BTTF. Ironically enough, these two users really don't get along - but both seem to really like the Marty as a fox idea. Not only was Marty played by Michael J Fox, but he is also very clever (especially in Part III). I also love the Lorraine as a cat and George as a lemur ideas by Kleenexwoman and Doc as a wolf idea from Flaming Trails.

Anyway, what are your thoughts? Biff would most obviously fit as a jackass - but in with keeping it to the smaller furry variety, Biff would probably best fit as a pitbull.

That sounds like a great story. I wonder what Doc would be.

I know Kleenexwoman has disagreed with Flaming Trail's assessment of Doc as a wolf. She suggested a mandrill, as Doc was very clever and adept at using tools. It'd be smaller than a wolf, so it probably would fit in better with the theme.