Deep: Freediving, Renegade Science, and What the Ocean Tells Us About Ourselves

by James Nestor

Every year on the same day, at the same hour, usually within the same minute, corals of the same species, although separated by thousands of miles, will suddenly spawn in perfect synchronicity.

Scholander found that a person need submerge only his face in water to activate these life-lengthening (and lifesaving) reflexes. Other researchers tried sticking a hand or a leg in the water in an attempt to trigger the reflex, but to no avail. One researcher even put volunteers into a compression chamber to see if pressure alone would trigger a similar diving reflex. No dice. Only water could trigger these reflexes, and the water had to be cooler than the surrounding air.

The most incredible transformation, she said, happened at around forty feet down. There, the force of gravity seemed to reverse; the water stopped buoying your body toward the surface and instead started pulling you deeper.

Though the brain represents only about 2 percent of the body’s weight, it uses 20 percent of the body’s oxygen.

At 250 feet, the pressure is so extreme that your lungs shrink to the size of fists and your heart beats at less than half its normal rate to conserve oxygen. Heart rates of freedivers at this depth have been recorded as low as fourteen beats per minute; some freedivers have reported heart rates of seven beats per minute.

These reports are the lowest heart rates for conscious humans ever recorded. According to physiologists, a heart rate this low can’t support consciousness. And yet, according to the divers, somehow, deep in the ocean, it does.

During a no-limits dive in 1996, Cuban freediver Francisco Ferreras-Rodriguez’s chest shrank from a circumference of fifty inches at the surface down to twenty inches by the time he reached his target depth of 436 feet.

You can stay submerged in a blacked-out state for about two minutes. At the end of two minutes, your body will wake itself up and breathe one last time before you die.

In about an hour, Nitsch will attempt to ride a weighted sled to a depth of eight hundred feet on a single breath, what would be a world record in the no-limits discipline in competitive freediving and the deepest freedive ever attempted.

Weddell seals, which can hold their breath for up to eighty minutes and dive to depths below 2,400 feet. The seals were also able to avoid decompression sickness by reflexively collapsing their alveoli, the small cavities that exchange gases in the lungs, at great depths.

NOBODY KNOWS THE MASTER SWITCH better than the ama, an ancient culture of Japanese diving women who once numbered in the thousands. For more than twenty-five hundred years, ama used the same freediving techniques, passed down from mother to daughter, to gather food from the ocean floor.

“When a man comes to the ocean, he exploits it and strips it,” she says. When a woman puts her hands in the ocean, that balance is restored.

Dallenbach concluded, correctly, that humans did not use facial vision; we too had a sixth sense of echolocation.

He honed these skills with the help of a blind activist named Daniel Kish, whom he’d met at a lunch for blind students a few weeks after first sensing the pillars at school. Kish, who had lost his own sight at the age of one, ran a nonprofit organization called World Access for the Blind. The program taught blind people how to use an echolocation system that Kish had developed called FlashSonar.

On the display are two spectrogram readouts of dolphin vocalizations called whistles. The whistle patterns are precise, each separated from the next by the exact same millisecond-long interval.

In 1961, he joined renowned scientist Carl Sagan and Nobel Prize–winning chemist Melvin Calvin, among other esteemed astrophysicists and intellectuals, in a semisecret group called the Order of the Dolphin. The purpose of the order was to communicate with extraterrestrials; its first goal was to crack the dolphin language code.

dolphins would never send clicks or whistles while the other dolphin was sending clicks or whistles. In other words, they never talked over each other.

The first step in saving a blacked-out diver is yelling “Breathe!” in his ears and calling his name. In the blacked-out state, vision and physical sensation disappear, but hearing remains, and it’s often heightened. Yelling, Pinon says, activates parts of the brain that have not yet shut down. This jolt can override the body’s reflex to close the throat so fresh air can enter the lungs.

If yelling doesn’t work, we have to remove the diver’s mask, tap his face, and start blowing on his eyes. The technique frequently revives blacked-out freedivers; often, they’ll come to and begin gasping for air.

During blackout, the closed larynx will keep water out of the lungs (a good thing), but it will also keep fresh air out of the lungs (bad). Many drownings in water are known as dry drownings, meaning they result from the larynx closing, not from water getting into the lungs.

In 2001, the world record for static apnea, held by a Czech named Martin Štěpánek, was just over eight minutes. In 2009, Stéphane Mifsud, a French diver, increased the record by 27 percent, to eleven minutes and thirty-nine seconds.

That nagging, need-to-breathe feeling you get holding your breath is triggered not by oxygen deprivation but by buildup of CO2. Comfort with this buildup is what separates good freedivers from great ones, or good ones from guys like me.

the Valsalva maneuver, is used by about 99 percent of the population, and it’s usually effective. But it doesn’t work when you’re freediving past around forty feet. As you dive deeper, air becomes more and more compressed in the lungs, until there isn’t enough left to push into the ears. The Valsalva method becomes useless.

Most freedivers and some jet pilots (who need to equalize quickly during ascents and descents) use the Frenzel method, which traps air inside the closed circuit of the sinus cavities and allows for immediate and thorough releases of pressure.

The next few weeks, I work with Prinsloo to develop a regimen. I read the Manual of Freediving, a 362-page bible of the sport, cover to cover. I scour the Internet, watching countless YouTube instructional videos and reading freediving blogs. I practice and practice.

In many ways, the waters of Trincomalee look about the same as they did thousands of years ago. Today, it’s one of the world’s best places to see and study sperm whales.

They can hold their breath for up to ninety minutes at a time and dive to depths of 10,000 feet. Yet, in two related and crucial ways—language and culture—sperm whales more closely approximate human culture and intellect than any other creature on the planet.

By their teens, bulls join groups, or gangs, of other bulls and wander the ocean looking for food—and sometimes for trouble. Bulls will eventually strike out on their own to live bachelor lives in the Arctic and Antarctic Oceans, visiting the equator—“for summer vacation,” said Whitehead—every spring to mate and socialize for six months before returning to their solitary winter homes.

Sperm whale clicks—which are used for echolocation and communication, and max out at 236 decibels—can be heard several hundred miles away, and possibly around the globe.

In air, a 236-decibel sound would be louder than two thousand pounds of TNT exploding two hundred feet away from you, and much louder than a space shuttle taking off from two hundred fifty feet away. In fact, 236 decibels is so loud that a sound of that intensity cannot...

Even underwater, sperm whale clicks are so loud they could not only blow out human eardrums from hundreds of feet away, but, some scientists estimate, vibrate a human body to death.

They can detect a ten-inch-long squid at a distance of more than a thousand feet and a human from more than a mile away. Sperm whales’ echolocation is the most precise and powerful form of biosonar ever discovered.

The sperm whale’s brain, like its clicks, both distinguishes it from a human’s and suggests surprising similarities between the two species. Six times the size of the human brain and in many ways more complex, the sperm whale’s brain is the largest brain that’s ever existed on Earth, as far as we know. The inferior colliculus in the sperm whale brain, which helps sense pain and changes in temperature and serves as an auditory pathway from one area of the brain to the other, is twelve times larger than a human’s; its lateral lemniscus, which processes sound, is two hundred and fifty times the size of a human’s. The neocortex, the part of the brain that, in humans, governs higher-level functions such as conscious thought, future planning, and language, is estimated to be about six times larger in the sperm whale brain than it is in ours.

In 2006, researchers at New York City’s Mount Sinai School of Medicine discovered that sperm whales had spindle cells, the long and highly developed brain structures that neurologists associate with speech and feelings of compassion, lov...

Sperm whales not only have spindle cells, but have them in far greater concentration than humans do. Scientists believe these cells evolved in sperm whales more than fifteen million years before they did in humans. In the realm o...

A nonscientist might call love, suffering, and compassion the stuff of poetry. And no poetry was ever conveyed without words or something like them.

“There are no fast results in this research,” he says. “That’s why so few people bother doing it.” Actually, he corrects himself, nobody is doing it. Of the twenty or so sperm whale scientists in the field, none dive and interact with their subjects.

SPERM WHALES PRODUCE FOUR DISTINCT vocalization patterns: normal clicks, for tracking down prey at distances of more than a mile; creaks, which sound, despite their name, like machine-gun fire, for homing in on close-range prey; codas, the patterns used during social interactions; and slow clicks, which no one quite understands. One theory is that bulls use slow clicks to attract females and scare off other males. The clicks are very similar to dolphin clicks but more complex.

Coda clicks, the focus of Schnöller’s work, are used only during socializing and are significantly different from clicks used to aid perception and navigation. They sound unremarkable to the human ear—something like the tack-tack-tack of marbles dropped on a wood table. But when the clicks are slowed down and viewed as a sound wave on a spectrogram, each reveals an incredibly complex collection of shorter clicks inside it. Inside those shorter clicks are even shorter clicks, and so on. The more closely Schnöller focused in on a click, the more detailed it became, unfolding on his computer screen like a Russian nesting doll. An average click lasts anywhere from twenty-four milliseconds (thousandths of a second) to seventy-two milliseconds. Inside these clicks are a series of microclicks, which themselves are separated by microseconds, and so on. All these tiny clicks inside the coda are transmitted at very specific and distinct frequencies. There could be even shorter, organized click patterns within these microclicks, but Schnöller’s machines—which record at 96,000 Hz, the highest speed available on most modern audio equipment—aren’t fast enough to process them. Schnöller tells me that sperm whales can replicate these clicks down to the exact millisecond and frequency, over and over again. They can also control the millisecond-long intervals inside the clicks and reorganize them into different structures, in the same way a composer might revise a scale of notes in a piano ...

“When you think about it, human language is very inefficient, it is very prone to errors,” Schnöller says. Humans use phonemes—basic units of sound, like kah, puh, ah, tee—to create words, sentences, and, ultimately, meaning. (English has about forty-two phonemes, which speakers shuffle around to create tens of thousands of words.) While we can usually convey phonemes clearly enough for others to understand them, we can never fully replicate them the same way each time we speak. The frequency, volume, and clarity of the voice shifts constantly, so that the same word uttered twice in a row by the same person will usually sound discernibly different, and will always show clear differences on a spectrogram. Comprehension in human language is based on proximity: If you enunciate clearly eno...

A calf swam over and faced Schnöller, then took the camera in its mouth. A group of adults immediately surrounded the calf and showered it with coda clicks. Seconds later, the calf let the camera go, then backed up and retreated behind the adults without ever looking at them. To Schnöller, the young whale looked ashamed. “It got the message not to mess with us.” He laughs. “That’s when I knew, they had to be talking to it. There’s just no other way.”

Hussey and his crew cut open the whale’s head, and hundreds of gallons of thick, straw-colored oil oozed out. The oil must be sperm, they thought (wrongly); this strange whale must be carrying its “seed” within its oversize head. Hussey named it spermaceti (Greek sperma, “seed”; Latin cetus, “whale”).

Ninety-five days later, the boat was rescued. There were two survivors: the captain and the man who had pulled the trigger. The harrowing tale served as the basis for Herman Melville’s novel Moby-Dick and, more recently, Nathaniel Philbrick’s nonfiction bestseller In the Heart of the Sea.

IF HUNTERS DON’T ERADICATE SPERM whales, pollution might. Since the 1920s, PCBs (polychlorinated biphenyls), carcinogenic chemicals used in the manufacture of electronics, have slowly seeped into the world’s oceans and, in some areas, reached toxic levels. For an animal to be processed as food, it must contain less than 2 parts per million of PCBs. Any animal that contains 50 ppm of PCBs must, by law, be considered toxic waste and be disposed of in an appropriate facility.

Dr. Roger Payne, an ocean conservationist, analyzed sea life for PCBs and found that orcas had about 400 parts per million of PCBs—eight times the toxic limit. He found beluga whales with 3,200 ppm of PCBs, and bottle-nosed dolphins with 6,800 ppm.

Payne and other researchers point to the baiji dolphin, a freshwater native of China’s Yangtze River, as a possible portent of the sperm whale’s fate. Considered one of the most intelligent of all dolphin species, the baiji dolphin has become functionally extinct due to pollution and other manmade disturbances. (At last count, there were about three baiji dolphins left.)

The fact is that nobody—not Prinsloo, Schnöller, or Buyle—really knows how risky these kinds of encounters are. Up until ten years ago, Schnöller told me earlier, nobody was diving with whales.

Universities and oceanographic institutions would never allow their researchers or students to dive with whales. Few would want to.

One of the longest-running sperm whale research programs is the Dominica Sperm Whale Project, headed by Hal Whitehead. The group studies sperm whale behavior by, among other things, following pods around and snapping photographs of flukes when the whales come up for air.

“They sell these to institutions for fifteen hundred euro,” he says, laughing. “I make mine from junk, and it works just as good.” Click Research, a new oceanographic manufacturing company he’s now building, will offer a version that works as well as the institutional model for only $350.