One of the advantages of the science of animal behaviour, which was founded 60 years ago by Niko Tinbergen and Konrad Lorenz, is that it has let us understand something of the essence of wild creatures: how they go about their normal lives in their natural state. It has also correspondingly enabled us to see, for the first time, that some behaviours exhibited by the animals we keep in captivity are not normal at all. Indeed, as we report today in the case of chimpanzees, they can be examples of considerable distress, or even incipient madness; and the cause seems to be captivity itself.
Zoos have not been unresponsive to the challenges of animal welfare in recent years. For example, it is a decade now since London Zoo moved its elephants from their entirely unsuitable concrete elephant house in Regent's Park to the greener and freer pastures of Whipsnade. Yet it is clear that despite the obvious value of zoos for education and the captive breeding of endangered species, there is a growing questioning of the virtue of keeping some creatures in captivity at all, not least the primates, our closest relatives in the animal world.