We, as humans, have actually developed a sense of social responsibility. We have gone beyond our basic instincts.

Studying chimps, I came to the conclusion that being evil is something that only humans are capable of. A chimp would never plan to pull another's nails out. The chimps' way of aggression is quick and brutal. I compare them to gang attacks.

It was both fascinating and appalling to learn that chimpanzees were capable of hostile and territorial behavior that was not unlike certain forms of primitive human warfare.

It's not a pretty picture, but there are reasons for hope.

What makes us human, I think, is an ability to ask questions, a consequence of our sophisticated spoken language.

I thought my life was mapped out. Research, living in the forest, teaching and writing. But in '86 I went to a conference and realised the chimpanzees were disappearing. I had worldwide recognition and a gift of communication. I had to use them.

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.