I have often noticed how primate groups in their entirety enter a similar mood. All of a sudden, all of them are playful, hopping around. Or all of them are grumpy. Or all of them are sleepy and settle down. In such cases, the mood contagion serves the function of synchronizing activities.

It is well known that apes in the wild offer spontaneous assistance to each other, defending against leopards, say, or consoling distressed companions with tender embraces.

Dogmatists have one advantage: they are poor listeners.

Science is not inherently good.

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?

We justify the inequalities by saying some people are just better and smarter than others and the strong should survive and the poor can die off.

The thinking is that we started evolving language not by speaking but by gesturing.