Sometimes your plant or building will come with an animal. These animals move about your island, and have little animations when you tap on them.
Another option to populate animals is by buying special animals from the “Specials” section of the store. These animals add to your harvest amount. The amount listed under their purchase price is the amount you will receive every time you harvest coins from your island.
For example, the Albino Dragon will give you a fixed amount of 5,000 coins for each plant or building every time you harvest.
Instead of a fixed amount per harvest, you could buy a special animal that gives you a percentage increase. If you have a Blue Dragon, for example, every harvest will yield 15% more coins per plant or building.