The voice of the natural world would be, "Could you please give us space and leave us alone to get along with our own lives and our own ways, because we actually know much better how to do it then when you start interfering."

Chimpanzees, more than any other living creature, have helped us to understand that there is no sharp line between humans and the rest of the animal kingdom. It's a very blurry line, and it's getting more blurry all the time.

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.

It's not that humans and non-humans are identical... but the lack of understanding that led to the slave trade is the same lack of understanding many people have about animals today. When slaves were brought over from Africa, many people believed they were not humans, that they didn't have feelings. Many people believe that primates and other animals don't have feelings, too, but they do.

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

Chimps are brutal, and it is so deliberate. The males go out and get near the boundary of their territory. And they walk very silently trying hard not to make any noise. They will climb into a tree and stare out over hostile territory for hours. They are waiting for the right opportunity. And then they attack.

A good mother is protective but not over-protective. She's patient, she's affectionate, she's playful, but above all she is supportive.