There are 40+ animals in Raise Animals that players can catch, raise, and put on display in their zoo. Every animal has certain attributes that make them better (or worse) than the other in the Index. You will have to go through all types of animals when you start playing the game, but the eventual goal is to have the best animals in your zoo that can make you rich. This Raise Animals tier list ranks all the animals, so you know which ones to go after.
