Cows, Pigs, Wars, and Witches: The Riddles of Culture

by Marvin Harris

Above all, the pig is thermodynamically ill-adapted to the hot, dry climate of the Negev, the Jordan Valley, and the other lands of the Bible and the Koran. Compared to cattle, goats, and sheep, the pig has an inefficient system for regulating its body temperature. Despite the expression “To sweat like a pig,” it has recently been proved that pigs can’t sweat at all. Human beings, the sweatiest of all mammals, cool themselves by evaporating as much as 1,000 grams of body liquid per hour from each square meter of body surface. The best the pig can manage is 30 grams per square meter. Even sheep evaporate twice as much body liquid through their skins as pigs. Sheep also have the advantage of thick white wool that both reflects the sun’s rays and provides insulation when the temperature of the air rises above that of the body. According to L. E. Mount of the Agricultural Research Council Institute of Animal Physiology in Cambridge, England, adult pigs will die if exposed to direct sunlight and air temperatures over 98° F. In the Jordan Valley, air temperatures of 110° F. occur almost every summer, and there is intense sunshine throughout the year. To compensate for its lack of protective hair and its inability to sweat, the pig must dampen its skin with external moisture. It prefers to do this by wallowing in fresh clean mud, but it will cover its skin with its own urine and feces if nothing else is available.