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

Perhaps our greatest distinction as a species is our capacity, unique among animals, to make counter-evolutionary choices.

If our ethical code makes a purely arbitrary distinction between humans and all other species, then we have a code based on naked selfishness devoid of any higher principle.

It's striking that Native Americans evolved no devastating epidemic diseases to give to Europeans in return for the many devastating epidemic diseases that Indians received from the Old World.