Animal Lover Achievement
Make an animal completely happy.
This achievement requires that you make a single animal completely happy for 20 minutes and can only be done in Challenge Mode. You can check an animal's happiness by going to Edit Exhibit>Animals>View Animals, and then using the bumpers to switch between animals. To unlock this achievement, you must fill then "Animal Happiness" bar the 100% (not just into the green) and keep it there for 20 minutes. This stat is basically just the average of the other four statistics, Hunger, Cleanliness, Habitat Happiness, and Social Need. Dont focus on this achievement as it will unlock early in Challenge mode without any effort most likely.