Even chimps understand the concept - if a troop of chimps enters a fruit tree, they will only pick the fruits that are ripe and leave the others growing. That is sustainability.

The least I can do is speak out for the hundreds of chimpanzees who, right now, sit hunched, miserable and without hope, staring out with dead eyes from their metal prisons. They cannot speak for themselves.

I don't think that faith, whatever you're being faithful about, really can be scientifically explained. And I don't want to explain this whole life business through truth, science. There's so much mystery. There's so much awe.

If we do not do something to help these creatures, we make a mockery of the whole concept of justice.

Louis [Leakey] was anxious to initiate a scientific study of these chimpanzees. It would be difficult, he emphasized, for nothing was known; there were no guidelines for such a field study; and the habitat was remote and rugged. Dangerous wild animals would be living there, and chimpanzees themselves were considered at least four times stronger than humans. I remember wondering what kind of scientist he would find for such a herculean task.

Anyone who tries to improve the lives of animals invariably comes in for criticism from those who believe such efforts are misplaced in a world of suffering humanity.

I wasn't trying to be a scientist. I only ever wanted to be a naturalist, like a David Attenborough.