Chimpanzees have given me so much. The long hours spent with them in the forest have enriched my life beyond measure. What I have learned from them has shaped my understanding of human behavior, of our place in nature.

I believe that the tragedy [like terror attack] that's caused so much grief and suffering to so many thousands and thousands of people has also served as a call to action, because many people now are re-examining their own value systems, and the churches, temples, mosques and cathedrals are packed to overflowing for the first time in years.

You may not believe in evolution, and that is all right. How we humans came to be the way we are is far less important than how we should act now to get out of the mess we have made for ourselves.

I believe the only hope for mankind lies in the hands of our young people.

But does that mean that war and violence are inevitable? I would argue not because we have also evolved this amazingly sophisticated intellect, and we are capable of controlling our innate behavior a lot of the time.

You aren't going to save the world on your own. But you might inspire a generation of kids to save it for all of us. You would be amazed at what inspired children can do.

To me, cruelty is the worst of human sins. Once we accept that a living creature has feelings and suffers pain, then by knowingly and deliberately inflicting suffering on that creature, we are guilty, whether it be human or animal.