The hardest part of returning to a truly healthy environment may be changing the current totally unsustainable heavy-meat-eating culture of increasing numbers of people around the world. But we must try. We must make a start, one by one.

I cannot remember a time when I did not want to go to Africa to study animals.

Chimps taught us we're not separated from the animal kingdom, we're a part of it.

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.

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

The greatest danger to our future is apathy.

The hardest part of returning to a truly healthy environment may be changing the current totally unsustainable heavy-meat-eating culture of increasing numbers of people around the world. But we must try. We must make a start, one by one.