A/N: The words hnau, eldila, and Oyarsa are from C.S. Lewis' Space Trilogy. I decided to use them here to make my point more clearly, because other professional authors have also borrowed these words he invented, and I hope that it's all right. The terms don't belong to me.
There was a world somewhere in another galaxy. It was called the "Animal Planet." It was covered in vast amounts of vegetation and trees all over the land, as well as grasslands, mountains, and oceans. Animals of all varieties lived there in peace and harmony, ranging from mammals, birds, and fish to reptiles, amphibians, and invertebrates like insects. Animals that had gone extinct on Earth lived here in abundance, like the Quagga, the Passenger pigeon, some of the dinosaurs, and even the Dodo bird. But what really made this planet stand out was its hnau, or "rational animals."
Birds were the most cultural, refined, and advanced of the hnau on the Animal Planet. They believed in progress, idealism, and science, and made lots of high technology for themselves over the millennia. They had the best clothes and the most unique forms of art and poetry. For many years, they were a highly religious people, but one year, they began to learn about the concept of modernity, and the "Enlightenment" was born. The Birdmen were able to create miracle medicines, build transportation like flying cars, spaceships, and rockets, invent useful gadgets and build magnificent houses for themselves, and even make weapons so powerful they could wipe out an entire enemy army with one blast. They were, of course, the pioneers of their world, and they mined the finest gold, silver, and diamonds under the earth. Birds were colorful, bright (in more ways than one), and a pleasure to look at as they flew through the sky, because they did have humanoid bodies, but they also bore wings, like any ordinary bird.
There were also the Apes and the Monkeys. They were the cleverest of the hnau on Animal Planet. Apes were simple scholars and thinkers, writing books and studying the books of other societies with a passion. The Apes led tribal lives, living in communities and harems of hundreds of individuals, and their homes were most often the jungles and the treetops. This was not to say that they were necessarily primitive. The Apes constructed ingenious tools and used them to build the craftiest and most elaborately decorated houses in their societies. The simple gadgets they made helped them to find food and water when they needed it. And the Apes lived somewhat spiritual lives, being in touch with the Great Outer Spirit that existed somewhere in the cosmos, which they said took care of them and gave them all the cattle and swine on the Animal Planet. It's said that they were found by Bird pioneers and, being mistaken for savages less cultured than they were, they were enslaved for a long time to do work for the Birds. This continued for a few thousand years, until a few Apes stood up and declared an end to the racism, inspiring their people and, in some cases, Birds as well, to help them shake off the shackles of slavery and racialism.
The Monkeys, in turn, swung through the trees and lived in nests and caves. They were less sophisticated than the Birds and the Apes, but they were even better hunters, and they could find their daily food better than any other hnau on the Animal Planet. Their culture was the same as that of the Apes, as scholars and thinkers, for Monkeys and Apes were more intelligent than the Birds at first assumed them to be. The Simians, as the Apes and Monkeys were known when put together into one group, were natural hunters, but they killed only for food and self-defense, never for sport or war. They even built excellent boats that were much like canoes, rowboats, and speedboats from Earth. The sense of humor of Monkeys was "extravagant and fantastic," while the Apes' sense of humor was usually more ironic.
Then there were the Dogs and Cats. Cats were a very proud and elegant people that walked around strutting their stuff. Their chief duty in life was to be models and actors, due to their beautiful appearance. Their fur coats were all they wore, because they were not ashamed of their appearance at all. Some of them, though, tended to be arrogant, because they were also aloof by nature, and they cared little for the problems of others unless there was something in it for them. Some of the Cats looked like big, wild cats, and the biggest Cats, Lions and Tigers, were most often in positions of authority in their race. It was risky, trying to be too honest or too straightforward with one of them, because they were subtle and quick-tempered. Domestic Cats were more easygoing, and though aloof, they didn't mind making friendships. Mixed breed Cats, like Domestic Shorthairs, were the most common. The Cats usually tended to be among the laypeople of the Animal Planet.
The Dogs were much more humble in nature, and they cared more for people. It was their self-chosen duty in life to be helpers and servants to other hnau. German Shepherds were law enforcement officers. Rottweilers were guard dogs. Bloodhounds sniffed out dead bodies. Pit Bulls were the military of the Dog people. And Beagles were considered to be the best friend another hnau could have. But some Dogs preferred to be laypeople, like the Cats. Yorkshire Terriers, Chihuahuas, Pugs, and Boxers liked a simple life at home, doing casual work for a living, although they were more than willing to make lots of friends outside of their families. Even some Cats had formed friendships with these smaller Dogs.
And then, there were the Lizards and the Frogs. Lizards lived secretive lives, usually as nomads in the wild, looking for other people to fight against. The Lizards were a race that was largely warlike, and many of its members fought and killed for blood, and nothing more. Some of them, however, had (somewhat) better desires, like gaining treasures and money, or the thrill on conquering a society that felt so secure before the Lizards attacked. Of course, as in any hnau, there were exceptions to these rules. Some Lizards were more honorable, and fought for good causes rather than just for the sake of it, and some of them were even peaceful creatures. But the fact that the majority were bloodthirsty killers led to some gratuitous racism on the part of other races.
The Frogs were strictly water-dwellers. They seldom spent more than a week away from their favorite lake or pond, or any lake or pond, for that matter. Boats were something the Frogs were talented at making, but they were even more proud of their natural swimming abilities, for they were the best hnau on the Animal Planet at swimming. Their gift in life was writing poetry and singing songs. Their croaking voices sounded much better when reciting or singing than an off-worlder would expect; even those of them that were Toads sounded almost as lovely as any good human singer. Unlike the Apes and Monkeys, however, they did not write down their poetry or their songs in books, because they believed books would ruin songs and poems. Besides, their bodies were almost always moist, and holding a book for a long time with hands like that would ultimately ruin the book. The Birds once considered this race to be stunted and un-lovely, not to mention backward, but when they heard the poetry and songs of the Frogs, many of them changed their minds, and forged friendships with the sapient amphibians, although some Birds still kept up racist attitudes.
The planet also had its share of eldila, or supreme beings. They dwelled in the Deep Heavens of Space, but frequently visited, and even talked to, some of the inhabitants of the Animal Planet. There was a Bird King for the Birds, a Simian Queen for the Apes and Monkeys, a Dog Master for the Dogs, a Cat Mistress for the Cats, a Lizard Scorekeeper for the Lizards, and a Frog Emperor for the Frogs. The Bird King and Simian Queen ruled justly but mercifully over their respective races, assisting them in times of trouble and admonishing them when they made serious mistakes. The Dog Master and Cat Mistress took care of the Dogs and Cats, but in different ways; the Dog Master trained his charges in the proper ways of living, and rewarded them handsomely, while the Cat Mistress gave every Cat his/her chosen coat of beautiful fur, and made certain they behaved themselves when they showed themselves off. The Lizard Scorekeeper was a lesser goddess who kept track of the kills a Lizard committed in his life, and determined their place in the afterlife, and the Frog Emperor had absolute power over the affairs of his humble Frog subjects.
Rounding out the eldila of the Animal Planet was the Oyarsa, the most supreme being of all on that world. He was the one who created the planet and its hnau, and it was also he that controlled the course of nature on the entire planet. None dared to challenge his authority, not even the eldila, and his word was absolute on the Animal Planet.
This was written by a lover of animals who wishes that there could have been sentient animals in existence on another world, which may not be completely impossible. If this world can exist in one person's imagination, think of what else other people can think of when it comes to world building.