Lady Rwebhu Kidh wrote:
What would be the difference between reincarnations and having imago deic animals, from a Biblical point of view? The Bible says that people do not reincarnate, but he also says that animals don't have the image of God. If we can change one, why could we not change the other as well?
From my perspective, reincarnation and other similar issues (such as the one you bring up) fall under the general principle of "responsible freedom"---a Christian author 
may (is 
free to) portray (speculate about) routine human reincarnation, or animals bearing the image of God, or nearly anything else. The question is whether the author 
should do so---whether we should 
exercise that freedom. The thing about reincarnation is that billions of people believe it, so using it in a story could be dangerous. Not so many people believe that animals are made in the image of God, so it's at least 
differently dangerous to write about a world in which they are.
(As an aside, I'd say that Lewis did that in Narnia---much like Tolkien, if the Tolkien experts on this forum are right, included reincarnation in his Middle Earth, just not for Men.)