I've considered making a thing where you could vote for your favorites, and it currently works with a few animals, but I don't know if it'd ever reach enough popularity to have a large enough sample size for high-confidence accuracy.
If you want to play with it, here it is:
http://zorua.me/animals/
Heck, it'd probably be easy enough to make that to work with Pokémon. Getting the images is far faster for Pokémon than finding Creative Commons or public domain animal pictures.