Zoobiquity by Barbara Natterson-Horowitz Read Free Book Online

became president of the United States in 1853. Few would characterize George H. W. Bush, Margaret Thatcher, David Petraeus, Fidel Castro, or Janet Reno as weak-willed, yet all suffered fainting spells while in office. To an observer, passing out might seem helpless, a physiologic act of surrender, even defeat. But, given fainting’s protective power, perhaps it’s time to revise this derogatory and uninformed view of syncope.
    Fight, flight, or faint. Fainting is the body’s way of flipping a circuit breaker. It halts the action and perhaps even a pursuer. It can defuse conflict. It can enable escape. Fainting and its related spectrum of “slowing down” behaviors remain with us because over hundreds of millions of years they have helped animals evade death. Embedded in fainting’s ancient physiology is an important lesson for how we respond to the things that scare us. Fighting or fleeing your enemy may work some of the time. But when fighting is futile and fleeing not an option, just being still may offer an even more powerful form of protection.
    Teens at the ear-piercing salon, fawns hidden in leaves, blood donors, and fish escaping predators have all inherited fainting’s death-evading neurocircuitry. Their conversing hearts and minds have bestowed upon them a respite—a momentary, deceitful reprieve that for eons has sometimes meant a way out.
    * There are some theories. One, the “clot-production” hypothesis, posits that a slow heartbeat or full-on faint helps animals avoid bleeding to death after an attack, since slow-moving blood under low pressure clots better. The less plausible “human violent conflict” hypothesis suggests a Paleolithic-era origin, speculating that fainting evolved in women and children as a way of taking them (but not men) out of harm’s way during tribal warfare.
    † Female robberflies sometimes employ a similar tactic to thwart unwanted sexual advances. Writes entomologist Göran Arnqvist, “If grasped by a male, they exhibit thanatosis (playing dead). Once the female ceases to move the male apparently no longer recognizes the lifeless female as a potential partner, loses interest and so releases the female.” Whether or how this insect rape-prevention strategy has implication for human beings is unclear, but Arnqvist posits that since feigning death is so widespread in the insect world, females may have adapted this strategy to protect themselves from unwanted copulations.
    ‡ Some experts believe that crucifixion is death by recurrent vasovagal syncope. During this horrible form of torture (from which the word
excruciating
is derived), you’re restrained from collapsing into a restorative horizontal position. You faint and recover without respite, and eventually succumb to low blood pressure and oxygen deprivation.
    § The fish heart has two cardiac chambers separated by a rudimentary valve; the mammalian heart has four chambers and four cardiac valves. When the heart’s valves close, they create clicks we call heart sounds. In humans, the shutting of the heart’s valves generates the iconic
lub-dub
sound.
    ‖ The Volvo car company once offered a heartbeat detector as an option on some of its models. Volvo claimed the machine could alert you to the presence of an intruder in the backseat of your car
before
you got behind the wheel.

THREE

Jews, Jaguars, and Jurassic Cancer
New Hope for an Ancient Diagnosis
    As veterans streamed home from Asia and Europe after World War II, doctors in the United States were battling a deadly threat on the home front.Five times the number of Americans who died at Iwo Jima and Omaha Beach were dying every year of heart disease. In response, the National Heart Institute launched what became the gold standard in long-term medical investigations: the Framingham Heart Study.Every two years, starting in 1948 and continuing today, thousands of men and women from that Massachusetts city go to special doctors. They give blood and other lab