You need to kill the following animals, domesticated animals do not count for the trophy, neither do bats.
* Armadillo: You can find these in the Frontier and in Mexico.
* Bears: You can find these in the Tall Trees area in the North.
* Beavers: These are in the Tall Trees area in the North.
* Bighorn: You can find this in the mountains in the Frontier and Mexico, and in abundance in the Tall Trees area of the North.
* Boars: You can find these in Pike's Basin and the Tall Trees area.
* Bobcats: You can find these in Mexico and the Tall Trees area.
* Buffalo: As you first enter the Great Plains from Thieves' Landing.
* Cougars: In the mountains and hills on the Frontier and Mexico.
* Coyote: On the Frontier and Mexico, listen for their whiny howls.
* Crows: All three areas, listen for their caws.
* Deer: All three areas
* Ducks: At Lake Don Julio at either side, they will be flying, listen for the distinctive "quack"
* Eagles: Tall Trees and Nikoti Rock areas of the North.
* Elk: Tall Trees area.
* Foxes: Near Riley's Charge on the Frontier and in the Tall Trees area in the North.
* Hawks: The Frontier and Mexico.
* Wild Horses: Any horse roaming any map that does not have a saddle on its back.
* Owls: All three maps, only at night.
* Rabbits: All three maps.
* Raccoons: All three maps.
* Seagulls: Blackwater near the water.
* Skunks: Around MacFarlane Ranch on the Frontier.
* Snakes: All three maps, listen for snake hissing or rattling while you are riding then check around on the ground.
* Songbirds: Near the twons on all three maps.
* Vultures: All three maps, usually near death.
* Wolves: All three maps, but in abundance in Mexico and the Tall Trees area.
These animals do not go towards 100% game completion. I take no credit for this guide, credit goes to
http://www.reddead.net/forums/thread-red-dead-100-guide-to-r...