Board Thread:Wiki discussion/@comment-25091239-20160702003854/@comment-25091239-20160703021724

And mammals, replies, birds, etc. are great categories for people who are new to the seris(if you don't remember this point it is my second one), while categories more specific than that are to empty and a lot of them would just have one or two members(like squids, spiders, and turtles).