Remember in the Introduction when I promised not to bore you with dry details? Well, I’m sticking to that promise, and I won’t go into the nitty-gritty of animal classifications or how I arrived at my chosen list of basic animal groups. Suffice it to say that there is a remarkably large classification system dreamed up by scientists that divides the entire animal world into groups, such as mammals and birds, only it gets much more complicated than that. And the scientists themselves are constantly changing their minds based on new information, and arguing about which beastie should go where, and why, and sometimes it seems they have as many possible reasons as there are animals. In the end it is an artificial construction designed to help us make sense of things, and however useful it is, it means very little to the animals themselves.
In order to make my writing task as manageable as possible, I have chosen the most generally accepted groupings as of 2011. For mammals, birds, amphibians, reptiles, and fishes I will be dividing them into groups based on their Order, which is a level of grouping that separates for example whales from bats, and rodents from rabbits. Every animal in a different Order has a different evolutionary history from those in a different Order.
For invertebrates, animals without a backbone, I have cheated and gone up the grouping ladder to the Class level, and sometimes even up to the very broad level known as Phylum. This is because there are a tremendous number of Orders when it comes to invertebrates, and not all of them seem very different to us. I doubt you would be interested in the relatively small things that separate eight different Orders of microscopic parasitic worms, for example, even though those differences are considered as evolutionarily important as the differences between elephants, kangaroos, and hedgehogs. Instead I will tell you about microscopic parasitic worms in general.
In total I have chosen 204 groupings of animals to describe, encompassing essentially the entirety of the known animal world. They will be named after the scientific term for their Order, because these are wonderfully strange and interesting words, and will be presented in alphabetical order within each volume. There will be separate volumes for Mammals, Birds, Amphibians, Reptiles, Fish, Invertebrates, and Miscellaneous. Don’t be worried about these words. You may find them boring, but they are simply a label. You don’t need to know them, and the information within will not focus on scientific names in any way.
As a final note, if you happen to actually be a zoologist or a taxonomist and disagree with my groupings because of this detail or that recent convention, please do understand that the groupings are largely arbitrary for my purposes as long as I have every animal, which I do. If you feel for example that I have done a tremendous disservice to rheas by not giving them their own Order, please remind yourself that it is between the rheas and me. If they are unhappy, I’m sure I’ll be hearing from them.