Medusa's Gaze and Vampire's Bite: The Science of Monsters (11 page)

But not the kind of shock that comes up in casual conversation. Being “shocked” to find out that a friend is cheating on a partner or that a loved one has unexpectedly died is not something that kills.

The type of shock that causes death has a single cause: not enough blood traveling to the brain and other organs. Emergency room personnel most commonly see hypovolemic shock, where massive blood loss means there’s not enough blood left in the body to be pumped by the heart to the brain. The same sort of situation occurs with cardiogenic shock, where a heart attack causes so much damage to the heart that it cannot pump enough blood. There is a profound drop in blood pressure, resulting in inadequate blood flow to all the organs, including the brain.

Then there’s neurogenic shock. Usually caused by physical trauma to the spine or skull, it disrupts neural signals sent to blood vessels by the brain. This is serious because these neural signals routinely tell the blood vessels to narrow or widen in order to regulate blood pressure. With the signals disrupted, the blood vessels relax and naturally widen. This causes blood pressure to rapidly drop because there is not enough blood to fill the (now wider) blood vessel system. With blood pressure too low, blood transport to the brain gets reduced or cut off entirely, unconsciousness follows, and shock sets in. Remarkably, giving somebody a sudden scare can also disrupt the neural signals to blood vessels and lead to a similar effect, which is commonly called psychogenic shock. This is what causes some people to faint at the sight of blood or upon seeing other psychologically distressing things.

Although the causes of these various forms of shock are different, they all result in the brain being denied the oxygen and glucose it needs to survive. When this happens, the brain starts having trouble
functioning. The symptoms are often the same: Patients become disoriented, nauseated, and dizzy while their limbs become cold, tingly, and stiff as a result of reduced blood circulation. In a sense, the tingly paralysis that people often feel in their legs after sitting for too long is kind of like a localized, nonlethal taste of what shock patients feel in all their limbs. Moreover, a lack of blood flow to the brain can trigger seizures that sometimes lead to a state of boardlike stiffness in the body.

Human bodies worked the same way thousands of years ago and the ancient Greeks would have experienced the identical symptoms of psychogenic shock. With this in mind, it is tantalizing to consider the possibility that the concept of Medusa’s petrifying gaze stems from someone who felt the icy grip of this shock upon seeing something frightening or worse, had a seizure from the experience, and entered a state of severe rigidity. But what of the strange notion that her hair was made of snakes? How did such a trait find its way into the myth of the monster, and what fears was this feature representing?

There are no living organisms that have heads covered in writhing snakes and, to date, there are no fossils indicating that such organisms ever existed. Why select snakes? Medusa could have had a head covered in tendrils like those on jellyfish or even tentacles like the limbs of a squid or an octopus. Yet the myths about her are consistent and specific: She always has hair of writhing snakes. This is not an accident.

Snakes kill people. Whether they are anacondas that squeeze the life out of humans stupid enough to swim in their jungle waters or cobras that inject venom with their fangs, snakes are a major threat to human life in many parts of the world today and there is evidence that this has always been the case. A 1978 study led by James Larrick at Duke University analyzed interactions between venomous snakes
and the Waorani of Ecuador’s Amazon rain forest. He found that 45 percent of the nearly six hundred individuals in the native population had experienced at least one snakebite and that about half of the people had been bitten more than once. As for the snakebite mortality rate, data collected on deaths over six generations indicated it had long hovered around 4 percent, roughly twice the 2.1 percent mortality rate that traffic accidents inflict on the developed world. True, with the invention of antivenins and emergency rooms, snakebites are now becoming less of a threat than they once were, but they were a terrible danger until very recently.

It is difficult to determine when highly venomous snakes and our primate ancestors first started mingling, since venom does not fossilize as bone does. However, venom injection mechanisms, like the hollow hypodermic needle teeth in venomous snake skulls, do sometimes get preserved and can hint at venom having once been present. Some fossil reptiles with hollow fangs have been dug up in Triassic sediments dating back to around two hundred million years ago, long before primates evolved. What these hollow fangs were used for cannot be determined for certain, but the paleontology team that made the find, led by Jonathan Mitchell at the University of Chicago, theorized in 2010 in the journal
Naturwissenschaften
that these ancient fangs were probably used for injecting venom. This suggests that venomous reptiles have been around since the days when mammals were only just beginning to evolve. Yet Mitchell’s toothy find, named
Uatchitodon,
is more similar to a lizard than to a snake and is unlikely to have been on the same evolutionary path as modern snakes.

Other work, led by Bryan Fry at the University of Melbourne and published in
Nature
in 2006, analyzed large numbers of reptiles and studied the genes associated with their mouth secretions. While doing this, Fry and his colleagues noticed that some lizards had proteins in their mouths that were very similar to those associated with venom in rattlesnakes. This hinted that the common ancestor of lizards and snakes, which lived some one hundred million years ago, may well have already been carrying some mild toxins
in its saliva and that these animals have long presented a threat to primates.
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Venomous snakes inhabited many of the landscapes where our ancestors evolved, and their venoms likely had the same effects then that they have on humans today.
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Such realities are important to recognize, because with two hundred thousand years of cohabitation, there has been a lot of time for evolution to shape the way the primate mind responds to snakes.

In modern society, where warning signs can be posted in dangerous areas and word of mouth can advise people to be wary of well-known threats, the idea of evolving an intrinsic fear is not easy to grasp. With communication so readily available, we do not need to evolve a fear of things like speeding automobiles and electrocution, since there are plenty of people to tell us it is bad to be hit by a car or shocked by an electrical cable. However, for most living things, warnings are not available, and this would have been the case for our ancestors.

Imagine a male primate ancestor keen to have a romantic evening with an attractive female. Suppose, eager to impress, the male goes hunting for a rabbit that he can feed to his potential mate. If, while searching for the rabbit, he does not see a coiled viper hidden in the underbrush, his chances of stepping on it are increased. If he does step on it, he is likely to be bitten, and if he dies from the bite, he will not have sex, will not father as many children as males who avoid vipers, and fewer of his genes will be passed along to the next generation.

Now consider a male who happens to spot the coiled snake, backs away, catches the rabbit (or not), has the romantic evening,
and fathers numerous offspring. If the reason for the male noticing the viper had anything to do with genetics, which is possible since genes do code for things like the ability to detect color and motion, then his genes are going to be carried on to his young, who will also be likely to spot hidden snakes.
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What all of this means is that there was probably strong evolutionary pressure for our ancestors to be able to notice snakes as immediately dangerous so they could avoid them. And psychological studies seem to support this.

In a 2001 study conducted by Arne Öhman, a psychologist at the Karolinska Institute in Stockholm, participants were presented with both benign images of flowers and toadstools and threatening images of snakes and spiders. These images were presented nine at a time in a slide show format, and the participants were given a little keypad for each hand. One keypad was to be used if all the images seemed the same, the other was to be used if contrasting images were seen, like benign images standing out from threatening images or threatening images mingled among benign ones. The researchers carefully measured the time between the moment an image was shown and the moment the appropriate button was pushed. Öhman reported in the
Journal of Experimental Psychology
that students responded much more quickly when snake and spider images appeared than they did when presented with merely benign images. He concluded that modern humans have an innate ability to notice dangerous animals quickly. Moreover, he argued that this innate rapid detection ability came about because evolution has selected for humans who
are able to spot threatening animals and thus not become ill or die before they can reproduce a lot. And he was not alone.

Numerous studies show that many primate species have a considerable fear of snakes. “The west coast of Tanzania has lots of really dangerous snakes. Cobras, black mambas, green mambas are everywhere,” explains primatologist Elizabeth Lonsdorf, director of the Lester E. Fisher Center for the Study and Conservation of Apes at Lincoln Park Zoo in Chicago. “People always ask me, ‘Don’t you ever worry about stepping on them?’ and I always say no, because I follow the chimpanzees and they just seem to know to avoid them. When the chimpanzees see snakes, they climb a tree and make a very specific vocalization that sounds like a questioning ‘hoo’ while staring intently in the direction of the snake. All of us in the field learn the call real fast.”

So why are snakes in Medusa’s hair? Because snakes are immediately recognized as a potential threat and generate fear that naturally weaves its way into monster mythology.

Whether the concept of Medusa was scary to ancient humans is not much of a question. If people believed that fossils were the result of her actions and if the feelings associated with psychogenic shock were related to what they believed becoming petrified must feel like, then she would have seemed like a real threat.

During the long journey from the days of the ancient Greeks to modern times, Medusa is never forgotten. She is often depicted in art, with particularly famous presentations of her hideousness by Michelangelo Caravaggio, Peter Paul Rubens, Benvenuto Cellini, and even Pablo Picasso. But was she frightening to these artists?

Cellini’s sculpture shows the hero Perseus, who slew Medusa, holding her severed head in victory. She is not alive and threatening but decapitated. In Rubens’s painting her snakes are hissing frantically as the blood pours from her neck, and Caravaggio’s Medusa has
a perfectly human face, admittedly ringed with snakes, that looks distressed. Her expression almost stirs a sense of pity. The decapitation is gross, but it isn’t really scary or threatening. A painting could easily have been made showing Medusa about to attack Perseus or fighting with him in the shadows, ready to gaze into his eyes, but such works were never made. This is not to say that ancient art never showed her beheaded. Many works did present Perseus victorious, but they were balanced out by art showing Medusa and her sisters alive and dangerous. That from the Renaissance onward, Medusa is always shown as beheaded, beaten, and dying hints that while she continued to be a fascinating subject for artists to paint and sculpt, she was no longer a widely feared monster. In contrast, Medusa’s decapitated head remained an object of fascination and, arguably, fear.

Late in the mythology surrounding Medusa, Perseus went on to marry the princess Andromeda, and during their ceremony a jealous suitor named Phineus
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led an attack to claim Andromeda for himself. Phineus was a tough opponent and the battle was fierce, but it was never one that he was going to win. Aside from the fact that Perseus
was part god, he was carrying around Medusa’s severed head in a silk bag.
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As Phineus lunged at the couple with his sword, Perseus shoved Medusa’s head in his face, turning him and his minions to stone. Many artists from the Renaissance and later periods painted this scene, including Jean-Marc Nattier, Sebastiano Ricci, and Luca Giordano, and most made the transformation of Phineus’s flesh from a healthy pink to a lifeless stone gray a focus of their work. In Ricci’s art, men hold up shields to reflect the horrific sight, some lose their balance, and many are frozen in place as they attack. Similarly, in Nattier’s painting, men scramble to hide their eyes from the petrifying gaze of the dead monster. There is an obvious sense of desperation that hints at something truly scary. Giordano shows Perseus wisely looking away as Phineus and his henchmen, with weapons drawn, are turned to stone.