Animals are items that can be purchased for your Farm. All animals will create Produce which in turn can be used in quests or sold at the Job Board. Animals can only create their respective produce if they are given Feed which can be purchased along side animals in the Store under the Farming section in the Animals category.
Most animals are purchasable through Gold, however the Turtle is the only animal that is available for Gems. As your Farm progresses more animals can be unlocked for purchase. The Puffin and Arctic fox along with their feeds can only be purchased if the Icestorm Island Expansion Pack is purchased.
To learn more about Animals please visit the Farming page.