Animals are as important a part of nature as trees, grass and flowers; and there is also some evidence that contact with animals may play a vital role in a child's emotional development. Yet animals are almost missing from cities; there are, broadly speaking, only three kinds of animals: pets, vermin and animals in the zoo. None of these three provides the emotional sustenance nor the ecological connections that are needed. Pets are pleasant, but so humanized that they have no wild free life of their own. Vermin are peculiar to cities and depend ecologically on miserable and disorganized conditions, so they are naturally considered as enemies. Animals in the zoo are seen only as occasional curiosities - and it has been said that animals living under zoo conditions are essentially psychotic; that is entirely disturbed from their usual mode of existence.