Finish an Era with a Village which has 250 Village Prosperity and only uses Animals
This development is awkward. Not hard, just awkward. The nature of animals is that their best symbiosis come from other resources, and their primary purpose in the later game is to create danger more than bountiful resources.
That said here is our advice. Build a desert town. our goal is the use the Rattlesnake and Kangaroo Rat/Desert Tortoise to generate a minimum of 11 Wealth per tile, pre-aspects. If you start with an animal focus your first Project should hopefully have an appropriate specialization and therefore be able to pick up some of the slack.
Your tile layout, therefore, should be Rat, Rat, Snake, Rat, Rat (or something to that effect).
The tricky part comes when humans get angry. The rattlesnakes create danger, you see, and you’ll need to balance placing your snakes with the human’s development. Too much danger and the humans will snuff out the snakes. Rude. Use more rats to help encourage growth in the city, and then replace with rattlesnakes when the village’s tolerance for danger grows.