Expected Behavior

I expected to see the animania creatures.

Actual Behavior

Nothing there :|

Steps to Reproduce

Start a new world, and explore a bit.

Version of Minecraft, version of Animania, Single Player or Server

1.12.2, animania 1.7.3, single player world.

Animania does not replace animals in an existing world.

Sounds like you may have not enabled spawning in the config. Have you installed Forge? Did you choose the correct installation from your launcher?

Closing this...