APN category says that here belong animals in forms that don't exist in the nature, but are bred by humans. Not sure if they meant only mammals, so we'll keep others here too.
Remember that not all your pets are domesticated animals - some are the same as those living in the wild so they will go to other category.
Again, avoid people and man made substrata - I know in this category it's more difficult but still doable. And again, we don't wish to see netting or bars in front of any animals.