For all the same reasons you mention Ras. I also found it interesting how they depicted the animals eating, that no matter how sophisticated they seemed the rest of the time they still ate like wild animals, as well as no matter how domesticated Mr. Fox tried to be the more he longed for a wild life. The question is are we meant to realize that some animals can just never be tamed or is it humans that are the wild animals, pretending to be happy with our cages? Depending on how one looks at it, its really two sides of the same coin.