The purpose of keeping any collection of wild animals in confinement should be threefold; first, to conduct as complete as possible a biological study of every species, especially those aspects which are too difficult or too costly to study in the wild and which may help in the preservation of that species in its natural habitat; second, to aid severely endangered species by setting up, under ideal conditions, protected breeding groups and, eventually, a reintroduction programme, so helping to ensure their future survival; thirdly, by the display and explanation of this work to the public, to persuade people of the vital necessity and urgency for the overall conservation of nature.

The Stationary Ark (1976)