As of just now, Methuselas has successfully imported animations into Civ IV using Maya. ;P That's right, Kiddos. I know what to do to import Civ IV animations in-game, using Maya. Feris was my test and I've got her using all the default animations from the "female trooper" model that Saibotlieh made. I have to fix some of the animations, though, 'cos they're pretty bad.
I'll start working on a tutorial that shows you what to do, via import/export and how to rig Civ Bips using Human-IK, so people can create their own animations, easily.
As for animals, what did you want? I would happily import some of my low-poly models, such as this:
The problem is, these "low poly" models (around 5-6k, mind you) are too big for Civ 4.
Maogota, where we come.
-EDIT-
Keep in mind, I'm still working the kinks out. For example, on Feris, her sword hand and her sheathed sword are not bound to their respected joints and don't show up, in game. So, she's basically swinging her fist around and I need to fix that. I have to test some more to see what's the problem with that. Also, there are still some transparency issues with textures. I'm still working on proper exports, but essentially, I can get new models and animations in-game now, using the tools I know how to use to model and animate, which IMHO are far superior.
Oh, and if you find a character from another game that you like or want, that's low poly and I can extract the animations from (mdl and nif, mostly), shoot me a link and the name of the unit, along with an image of the said character.. If it has enough animations and I can export them, I'll put it in-game.