"To eat liver, knowing that you, too, have a liver, brushes up against the cannibalism taboo. The closer we are to a species, emotionally or phylogenetically, the more potent our horror at the prospect of tucking in, the more butchery feels like murder. Pets and primates, wrote Mead, come under the category "unthinkable to eat." The same cultures that eat monkey meat have traditionally drawn the line at apes."