Chimpanzees are incredibly intelligent. They can learn more than 400 signs of American Sign Language. They have memories for spatial distribution, like numbers on a TV screen, way better than ours. You come onto the emotions: happiness, sadness, fear, and despair - all the things for which I was accused of being anthropomorphic when I ascribed them to chimpanzees.

In Tanzania, the chimps are isolated in a very tiny patch of forest. I flew over it 13 years ago and realized that, basically, all the trees had gone, that people all around the park are struggling to survive. It became very clear that there was no way to protect the chimps while the people were in this dire circumstance.

Maternal behavior helps when you have to be patient with nonverbal creatures.

Here we are, the most clever species ever to have lived. So how is it we can destroy the only planet we have?

You cannot share your life with a dog, as I had done in Bournemouth, or a cat, and not know perfectly well that animals have personalities and minds and feelings.

The most important thing is to actually think about what you do. To become aware and actually think about the effect of what you do on the environment and on society. That's key, and that underlies everything else.

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.