I think the main reason animals work so well in stories, especially those for children, is that it's quite easy to create rather extreme characters. Since they're not human their characters can be slightly more believable even if they do seem a bit wierd. With extreme characters you can make the ideas or points in a story very clear, which makes things easier for a child to understand and even as an adult it may have a harder impact on you.
EDIT: Actually I used to love Jack London's stuff like "White Fang" and especially "Call of the Wild".
Edited by - Recusant on 4/14/2004 12:13:27 AM