Monkeys, gorillas, they have brains and we have a brain, but they don’t have this thing, the thumb. They can’t move it opposite the way we do. The inner digit on the hand of man, that might be the distinguishing physical feature between ourselves and the rest of the animals. And the glove protects that inner digit. The ladies glove, the welder’s glove, the baseball glove, et cetera. This is the root of humanity, this opposable thumb. It enables us to make tools and build cities and everything else. Maybe more than the brain. Maybe some other animals have bigger brains in proportion to their bodies than we have. I don’t know. But the hand itself is an intricate thing.
The genetic similarities between humans and primates are very clear when you see Mick Jagger. Regarding the differences, we have the thumb, as the text explains, but we also have the fact that primates don´t have a white sclerotic, so you can´t see where they are looking at. This has plenty of evolutionary implications, as José Cervera has explained in this conference very well.
From a literary point of view, American Pastoral is a great book, so is The World Accoding to Garp, by John Irving. However, neither books should be read by parents that are inclined to suffering about their children too much.