I've always loved stories about animals and I always will.
When I was a kid my favorites were the Brian Jacques Redwall Series, the novels Watership Down and The Hobbit, and of course the Teenage Mutant Ninja Turtles comics and TV series.
In third grade when I started writing my own stories, I chose to use a squirrel as my protagonist. (I guess I knew a thing or two from climbing trees in the backyard? - I never had dogs or cats.)
In the Redwall Series, Brian Jacques presents us with a whole universe of animals, each with it's own peculiar habits, moral code, language intricacies, and geographic location. The mice were the regular folk. The rats were evil. The badgers noble and kingly. Otters were a working class, good-natured, lovable species. Ferrets and Shrews and Foxes were tricksters and thieves. Hares were cunning, athletic and witty.
(Wow...I have so much respect for Brian Jacques, and for J.R.R. Tokien and C.S. Lewis and George R.R. Martin and Gene Roddenberry and anyone else who created and sustained an entire world)
Fantasy worlds are invaluable for kids because they hold a mirror up to the real world.
So here's to all the world creators out there. I don't know how in hell you keep your notes straight.