The more self-aware an animal is, the more empathetic it tends to be.

Armies are a purely human invention. Most soldiers who go to war nowadays don't even do it because they're inherently aggressive.

I sometimes try to imagine what would have happened if we’d known the bonobo first and the chimpanzee only later—or not at all. The discussion about human evolution might not revolve as much around violence, warfare and male dominance, but rather around sexuality, empathy, caring and cooperation. What a different intellectual landscape we would occupy!

We would much rather blame nature for what we don't like in ourselves than credit it for what we do like.

The possibility that empathy resides in parts of the brain so ancient that we share them with rats should give pause to anyone comparing politicians with those poor, underestimated creatures.

Exclusive homosexuality is not very common in nature.

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?