Surviving the Extremes: A Doctor's Journey to the Limits of Human Endurance (16 page)

Activity began picking up under Callahan’s raft. Large fish were starting to cross his narrowly circumscribed hunting zone. By the thirteenth
day he had missed so many times that he could no longer concentrate. Absentmindedly, he took a potshot as another swam by, and to his complete surprise, he hit it. The 4-foot fish thrashed wildly as he brought it aboard. At all costs he had to prevent its snapping jaws and the impaled spear tip from puncturing the raft’s air chambers. He stabbed the fish in the eye, hoping to paralyze it, but that made the creature’s motions even more violent. Desperate to protect his raft, he wrestled with the fish, finally cracking its spine.

Callahan had won the grim death match. Now he prepared to eat his opponent. His survival instinct, intensified by hunger, had turned him into a vicious killer, but now, as those primitive impulses subsided temporarily, he was overtaken by a higher reaction: a sense of guilt for having brutally destroyed such a beautiful creature—a fellow mammal, a dolphin.

The capacities to feel guilt and appreciate beauty would seem to be odd evolutionary developments. Like other higher feelings, such as sympathy, mercy, duty, loyalty, honor, and self-sacrifice, they seem hindrances to survival. But natural selection has fostered the development of noble feelings. They appear in higher animals along with more obviously valuable brain functions such as reasoning and memory, and it is unlikely they developed accidentally. It may be that they aid survival by endowing the will with something to stimulate it, intensify it, and make it work both for the individual and the species.

It worked for Dougal and Lynn Robertson who, with their twin boys, teenage son, and teenage son’s friend, were adrift in the Pacific after their 43-foot schooner was attacked and destroyed by killer whales 200 miles west of the Galapagos Islands. What kept them going was what Lynn called their need to “get the boys to land.” Responsibility provided a motivation stronger even than that of self-preservation. When latent primitive impulses are drawn up alongside the noble feelings, the combination creates formidable means for survival.

After seven days in a lifeboat, the Robertsons thought their ordeal was over when they spotted a freighter heading toward them. They
fired signal flares, waved, and yelled as loud as they could, then fell silent as the huge ship passed by. Up to then they had been anticipating rescue—a somewhat dependent mental state. The bitter disappointment ignited in them a fierce will. “To hell with them,” Dougal said. “We will survive without them.”

Knowing that their fates were in their own hands transformed them. Dougal felt “strength flooding through me . . . and the aggression of the predator filling my mind. We had brains and some tools. We would live from the sea. From that instant on, I became a savage.”

First they needed water. Their supply was running low and they had no solar still. The skies overhead were cloudless, but they were drifting westward into the Doldrums, an area of the Pacific where there is more frequent rainfall. It wouldn’t do for them simply to hold their mouths open when it rained. They would need to use every bucket available, including the one into which they urinated. The best rain catcher, they knew, would be the canopy over the raft. If properly shaped, it could act as a funnel, collecting water and channeling it into a container.

And they would need food. Attempts at fishing had so far been fruitless. Fish were collecting under the boat, but only small ones. In any case, they would not be able to catch large ones, since they had neither spear nor gaff. With his knife, Dougal was able to stab some of the fish, but the amount of food they provided was barely equal to the calories expended in catching them, not to mention the additional energy lost in anxiety over the possibility of losing the knife overboard.

The same day that the freighter changed them from passive victims to aggressive predators, another ocean traveler provided them with their key to survival: a turtle got entangled in the line of the sea anchor they were using to stabilize the raft. They quickly tied its flippers and heaved it upside down into the boat. Dougal pulled on its beak, its claws thrashing helplessly, and slashed its throat, spurting blood everywhere. After its shell was hacked off and insides sectioned, the 80-pound turtle was reduced to about 20 pounds of turtle meat. Washing the blood off his hands, Dougal knew that before the freighter he would have recoiled at the thought of what he had just done. Now
he would do whatever it took to keep his group alive. He was determined to create a niche for them in the ecology of the ocean. Yet when man enters an ecosystem, he doesn’t necessarily enter at the top. Dougal and his family were somewhere in the middle. He cleaned his hands in the bottom of his boat rather than over the side; he was afraid the blood from his hands would attract a creature higher up the food chain.

The shark is the most efficient killing machine ever created. It has more ways of seeking out and destroying a target than a cruise missile. Sharks have been around for 400 million years—they’re twice as old as the dinosaurs. Early models were over 50 feet long. Like many machines that have undergone years of development, their size has been reduced while their efficiency has improved. Modern versions are up to 20 feet long and can weigh over 4,000 pounds—longer and heavier than most cars.

Sharks are not intelligent; they don’t have to be. They have a remarkable collection of sensory guidance systems that allows them to home in on a target. They can be alerted by sound more than a mile away and can smell a drop of blood or urine that’s been diluted 100 million times. Their nostrils function independently, so by turning their heads they can constantly correct their path toward the smell. Once they get within a few hundred feet of their target, the lateral line system comes into play. This consists of a series of fluid-filled holes along either side of the body that detect vibrations, particularly discordant ones, such as motion from a struggling fish or an uncoordinated swimmer. This works in tandem with a low-light vision system in which a layer of silver crystals at the back of the eye reflects incoming light so that it crosses the eye twice, thereby increasing contrast and perception of motion. At a few feet from the target, electrical detectors are activated. These are jelly-filled sacs in the head called ampullae of Lorenzini, which are extremely sensitive to the current generated by muscle contractions: they can detect the voltage in a single nervous twitch and even, perhaps, in an impulse of fear.

Sharks can stimulate quite a few fear impulses, as they did in my dive partner and me when we were diving off the Galapagos Islands while conducting a fish survey. I suddenly found it too dark to write
on my counting slate. Looking up, I saw a shoal of hammerheads passing overhead, obscuring the light. One curious shark swooped down and bumped my partner. This is something they often do before feeding, much as a choosy shopper might test the consistency of a melon. We placed ourselves back-to-back, ready to defend ourselves. The shark, however, left to rejoin its companions. Either it wasn’t hungry or it had determined that my partner wasn’t ripe.

A shark’s behavior may be unpredictable, but its potential for destruction is unequaled in the animal world. Once it decides to lock onto a target, it arches its back and its normally graceful swimming style becomes erratic. The largest sharks accelerate toward the surface at up to 40 miles per hour, striking with such force that they often drive their victim and themselves momentarily out of the water. A shark’s bite is an attack by over two hundred razor-sharp triangular teeth arranged like rows of ripsaws inside jaws that close with the force of a bulldozer. The upper jaw has teeth 2½ inches long for cutting. Teeth in the lower jaw slant backward for gripping. Sharks cannot chew, so they thrash their heads from side to side to tear off chunks of meat. The first strike may be just for “sampling,” though that may not be much consolation to the human victim, since the sample may be an entire limb or half a chest cavity. The shark may then decide the attack was a mistake, lose interest, and swim off, leaving the victim to die from massive tissue loss and hemorrhage.

Sharks turn castaways into prisoners. They patrol all the oceans. The threat of an attack prevents a sailor from leaving his raft for a swim, confining him to a space smaller than a jail cell and denying him the exercise needed to counteract the physical effects of prolonged immobility. Skin will break down if it is in constant contact with any surface, whether a bedsheet or a rubber raft. The process speeds up when the skin is coated with a caustic liquid such as urine or seawater. In the case of people too sick to eat or unable to get food, their fat cushion disappears, and as a bone becomes more prominent, it can wear through the weakened skin. Debilitated patients who are not fed, washed, and turned frequently will develop pressure sores, sometimes with bones poking out. Castaways who cannot exercise get the same
sores—made all the more painful by the ever-present salt continually washing into the raw wounds.

And there are the mental effects: not being able to leave the raft can make the sailor stir-crazy, and the sight of sharks following the boat is a constant reminder of what will happen if the raft sinks.

A human’s place in the food chain may be below a shark’s, but it is above that of almost every other sea creature. Since all oceangoing fish are edible, humans can eat whatever they can catch. Spears are the best weapons. Resourceful castaways have made spears from knives tied to sticks and then attracted fish at night with a flashlight or by reflecting moonlight with a mirror. Fishhooks have been made from safety pins, compass needles, and fish bones. Biscuits or barnacles can serve as start-up bait; better bait can be made from the first fish caught. Anything from rope to shirtsleeves to shoelaces can be used for fishing line. Even with no bait, no hook, and no line, a fish can be captured. One desperate sailor dangled his finger in the water and grabbed small fish that bit into it.

Marilyn Bailey, adrift in the Pacific with her husband, Maurice, for 117 days, thought of using her fingers to catch fish but then hit upon a less painful method. She cut a big hole in the side of a kerosene can, put bait inside, and lowered it into the water by its handle. When a fish swam into the can, she simply scooped it up and deposited it in the bottom of the boat. Another way to scoop food from the sea is with a sock. Oceans are filled with tiny organisms—plankton and krill—that lie suspended in the water. They are the world’s favorite seafood, preferred by whales everywhere. A nylon or silk sock trailing in the water will act as a filter to collect a serving of foul-smelling, repulsive-looking, but highly nutritious soup.

Thor Heyerdahl, the famous Norwegian anthropologist-explorer, used that basic technique and many others like it when he set out on a reed raft, the
Kon-Tiki,
to prove that ancient peoples were capable of crossing vast oceans. One other food-gathering technique was to delegate the job to a small fish, called a remora, which attaches itself to larger fish by means of a sucker on the top of its head. When he caught one, instead of eating it, Heyerdahl tied a line around its tail
and dropped it back into the water. The remora would soon attach itself to another fish with a suction strong enough to bring both on board when the line was pulled in. This ancient method is still used by Polynesians—an example of the human heritage of animal exploitation. The tradition was given immediacy by Marilyn and Maurice Bailey, who adopted it to stay alive.

Without a still or rain collector, or a spear, or a fishhook, or a fishing line, or even without socks, it is still possible to live off the ocean. In fact, the record for the longest survival at sea, and perhaps for the greatest ingenuity, belongs to Poon Lim, a man who had none of those tools but did have a fierce will to survive. Lim was a Chinese seaman serving in the British Merchant Navy during World War II when his ship was torpedoed and sunk by a U-boat in the South Atlantic. Floating alone on an open wooden raft, he managed to stay alive for 130 days. To provide himself with water, he ripped open his life jacket and allowed the canvas inside to become saturated each time it rained. To catch food, he made a hook out of a spring inside his flashlight and then made others by bending nails that he pulled out of the raft with his teeth. He unraveled some heavy hemp rope to make a fishing line and baited his hooks with biscuits. When he caught a fish, he cut it up with the edge of the biscuit tin.

Poon Lim was finally picked up off the coast of Brazil by a fishing boat. He had lived off the sea for over four months yet lost only 30 pounds. He had to wait three more days before being taken to shore because he appeared so fit to his rescuers that they felt no need to interrupt their fishing trip.

Theoretically, no one should die of hunger on the high seas. There is a constant parade of fresh food. However, it is not easy to catch enough of it, and what you do catch will not make a balanced meal. A human diet should contain about 60 percent carbohydrates, our preferred type of fuel and the one our bodies can’t manufacture. We get them by eating plants or at least by eating animals that eat plants. But the wisps of algae that stick to the bottom of a boat are inedible, and ocean-traveling fish are not grazers. To maintain optimal physical performance, a human needs to eat about a pound of carbohydrates
a day, yet the amount floating or swimming in the ocean is virtually zero.

Carbohydrates are pure fuel. They are made only of carbon, hydrogen, and oxygen, three highly flammable elements that provide a lot of energy when burned. When formed into simple combinations, they are called sugars. Sugars burn like paper. They ignite quickly, burn rapidly, but do not last long—a quick burst. When the same three elements are combined in a more complex way, they are called starches. Starches burn like wood. They require more heat to get going, but once they catch, they burn a lot longer and provide a lot more energy—a sustained release. Carbohydrates have no function in the body other than to provide heat and power. The liver and the muscles store them as readily accessible fuel depots. Once these storage areas are filled to capacity, the overflow of carbohydrates is converted to fat by removing some oxygen and rearranging the same three elements into a denser pattern. Fat is a concentrated fuel that can store energy more efficiently for the longer term. Humans make fat from excess carbohydrates, but they also obtain it directly by eating other animals that have already done that storage job for themselves. Unlike carbohydrates, fat is essential to maintain vital body functions like blood clotting, hormone production, digestion, and nerve insulation. The vast majority of it, however, is dumped into otherwise empty fat cells, which are present almost everywhere in the body, especially around the abdomen, hips, and buttocks, where their storage is sometimes too obvious. For a given weight, fat provides twice as much energy as carbohydrates. Looking at it the other way, losing a pound of fat requires twice as much work as burning off a pound of carbohydrates. This is why eating fat makes you fat.