But let us not forget that human love and compassion are equally deeply rooted in our primate heritage, and in this sphere too our sensibilities are of a higher order of magnitude than those of chimpanzees.

But the largest number of primate species--thirty-four--have a promiscuous system in which females routinely associate and copulate with multiple males.

Though bonobos tend to be a lot hairier than us—and they don’t build houses or churches or Pentagons like we do—these primates look and act remarkably human. They often even go beyond the merely “human,” and enter the realm of the truly “humane.

A century ago, people laughed at the notion that we were descended from monkeys. Today, the individuals most offended by that claim are the monkeys.