Debra has a posable muskox here in Free Stuff. She also has a bison for sale over at Vista Internet Products, which is probably closer to what you're looking for.

The only Poser crocodile that I know of is part of brycetech's commercial collection. It's only $7 if purchased separately; not a bad deal, actually. You can find it over at 3D Commune.

If you don't need to pose it, you can find a free crocodile model by Tom Mueller at 3D Cafe.