The evolutionary struggle for survival is really a self-serving series of blows and stabs, and yet it can lead to extremely social animals like dolphins, wolves or, for that matter, primates.

Darwin wasn't just provocative in saying that we descend from the apes - he didn't go far enough. We are apes in every way, from our long arms and tailless bodies to our habits and temperament.

We are territorial, power-hungry and even more brutal than chimpanzees.

It is not only visitors to the zoo who are fascinated but uneasy in the presence of chimpanzees; the same is true of scientists. The more they learn about these great apes, the deeper our identity crisis seems to become. The resemblance between humans and chimpanzees is not only external. If we look straight and deep into a chimpanzee’s eyes, an intelligent, self-assured personality looks back at us. If they are animals, what must we be?

Wild groups of chimpanzees attack their enemies like gangs. What they completely lack, precisely because of their strong territorial behavior, is a friendly relationship with their neighbors.

It wasn't God who introduced us to morality; rather, it was the other way around. God was put into place to help us live the way we felt we ought to.

If you are a cooperative animal you need to watch what you get. If you, or even a whole community, invest in something but then a few individuals receive a much larger return, it's not a good arrangement. If it happens consistently, it's time to look for an arrangement that is more beneficial. That's why we're so sensitive to how rewards are being divided.