WHEN A WHALE DIES in the open ocean and sinks through the sunless depths to the seafloor, it does not simply disintegrate or gradually disappear beneath layers of sediment. Instead, it bursts into life. It becomes an underwater oasis where profusions of astonishing creatures engage in a macabre bacchanal. Slimy, eellike hagfish burrow mouth-first into the ample carcass, absorbing nutrients through their skin. Ghostly octopuses latch onto the leviathan, tentacles filigreed as if in ecstasy. Snow crabs help themselves to pinchfuls of soft tissue. A few years later, when all skin, muscle, and fat is gone, the feast continues. Bone-eating worms embed themselves in the whale’s skeleton, their acid-secreting roots dissolving marrow as their feathery red gills flutter in the currents. Thick mats of bacteria — white, pink, yellow — spring from ribs and vertebrae like moss on a log. “It is as though the whale were a piñata cracked open, flinging bright treasures,” writes Rebecca Giggs in her scintillating debut, Fathoms: The World in the Whale. “Decades may pass, a hundred years even, before nothing remains — only a dent that holds the dark darker.”

Of all the species that eat whales, none is as voracious as our own. We have consumed whales, literally and figuratively, for thousands of years, pushing some populations to the brink of extinction. We have hunted them for their meat, used their oil to lubricate factories and illuminate city streets, and turned their teeth into piano keys. We have snatched them from the wild, bottled them like goldfish, and forced them to perform circus tricks. We have plunged microphones into the ocean to record their mesmerizing songs and merged their melodies with our own. Whales have consumed us, too. They have consumed our thoughts, breached our collective consciousness, populated our myths and dreams. They have sponged up our chemical pollutants and ingested our detritus. In 2012, a sperm whale washed up on the shores of Andalusia, Spain, with a flattened plastic greenhouse in its stomach — complete with tarps, ropes, and flower pots — along with bits of mattress, coat hangers, and an ice cream tub. Much tinier yet widespread ocean contaminants, such as heavy metals and pesticides, move up the food chain, concentrating in the bodies of the largest and longest-lived marine animals, including whales. When people eat whale meat, its accumulated toxins return to the species that originally produced them, flowing into human blood, settling in human flesh and breastmilk.

Fathoms is a profound meditation on the mutual devouring of humans and whales. It bends the familiar tale of Jonah into an ouroboros: whale swallowing human swallowing whale. Giggs explores how whales have permeated our lives and the many ways we have invaded and transformed theirs. Each chapter orbits a different aspect of this long and fraught relationship — commodification, pollution, voyeurism, adoration, mythology — swerving wherever Giggs’s extensive research and fervent curiosity take her. We learn of baleen corsets, cetacean taxidermy, cryptozoology, the history of whaling, whale songs hurtling through space, a beluga that tried to speak English, the purportedly therapeutic practice of bathing inside the body of a decomposing whale, and how noise pollution disrupts cetacean navigation and long-distance communication. At the beginning of each chapter, Giggs offers a telegraphic preview of the text that follows: a series of enigmatic phrases separated by dashes. Arranged on the page like a beachcomber’s haul on the sand, or the eclectic contents of a deceased whale’s innards, the textual fragments echo one of the book’s central concerns: finding the hidden connections between seemingly unrelated pieces of the world’s flotsam and jetsam — between its wonders and its wrecks.

Giggs’s prose is fluid, sensuous, and lyrical. She has a poet’s gift for startling and original imagery: deep sea fish resemble “bottled fireworks, reticulated rigging, and musical instruments turned inside out”; a whale in the distance looks like a “pale lozenge” rolling in water; and the songs of humpbacks are “ululating bowwows that wind up and unwind, interspersed by clanks and spackling chitters, [… a] licked fingertip dragged over rubber[,] [a] metal train bridge rattling[,] [… and] glassware, tinkling in a flight attendant’s trolley during turbulence.” The lushness of her sentences and the intensity of her vision inspire frequent rereading — not for clarity, but for sheer pleasure and depth of meaning.

Fathoms is as much a triumph of imagination as of intellect. Whereas many of today’s nonfiction writers exalt screen-ready narrative as the pinnacle of the form, Giggs is more versatile and innovative in her approach, melding journalism, history of science, and nature writing with intimate recollections, fanciful jaunts, and insightful contemplation. She sometimes devotes several pages to close examination of a single fact, phrase, or image — a photograph of a Styrofoam cooler lid, for instance — tumbling it in her mind like a pebble in the surf, polishing the ostensibly mundane into gleaming epiphany. That particular chunk of Styrofoam, Giggs tells us, traveled along rivers to the Arctic Ocean, where it was frozen in ice floes hundreds of miles from land and eventually liberated as the ice thawed. “The meltwater, a symptom of climatic warming,” Giggs continues,

keeps on disgorging these sorts of symbols, as though history didn’t move in a line, but in a spiral. […] Things that were lost or forgotten reappear, strangely altered by context, [… i]n unoccupied and hard to access places. [… P]eople are pained, and perhaps blackly awed, to discover human presence bestrewn ahead of their arrival. […] Icebergs opaque with wet wipes like browning hibiscus. That tiny seahorse pinched onto a Q-tip. […] In the belly of a whale, the greenhouse; and an unopened tin of Spam found six miles down in the stygian depths of the Mariana trench.

Even when describing past events with few surviving records, or something she has not witnessed directly, Giggs uses all her artistry to animate the scene in vivid detail. In one passage, she envisions how someone roaming a beach in twilight might mistake a dead whale for the supernatural:

Out of the blue, now: a lumpiness in the shallows. […] Sea fleas shiver its outline, reeking with punctuality. Its mass is rocked by fractional waves. […] A whole hut of flesh. Something like hundreds of jellicate teeth in linen. […] A rill of organs inside weird, bog-man leather. […] The bones of a behemoth, a titan, a troll. […] The monster has no face. But if there is a dog, the dog’s face is barking.

Giggs resists the naïve and romanticized, marveling at the beauty and complexity of our planet, while also confronting its horrors, especially the outsize horror of humanity’s ecological blunders. She writes of rainbows that form in the steamy geyser of a blue whale’s breath, and whale songs that travel more than 1,600 miles from Puerto Rico to Newfoundland. She writes, too, that industrial whaling may have “subtracted major symphonists from the sea” and describes how a boisterous crowd, clamoring for selfies, killed a rare baby dolphin. In a particularly disturbing passage, we learn how a buildup of human refuse has increased populations of kelp gulls along the Argentinian coast, which has in turn resulted in more gulls swooping down on surfacing whales, pecking open wounds in their backs to eat their skin and blubber.

A pivotal scene takes place toward the middle of the book: during a tour of whaling ships in the port city of Shimonoseki in southwestern Japan, Giggs is offered a bowl of soup with a few pieces of minke whale floating in it “like autumnal leaves.” A longtime vegetarian, she makes a snap decision: “While I’m examining the shred with my tongue, I can feel my brain turning over. The whale in my bowl. The whale in my mouth. The whale swallowed into me.” Some anthropologists, she explains, have proposed that anthropomorphization evolved in our ancestors as an aid to hunting. Individuals who adopted the perspective of their prey were presumably more successful hunters, and therefore more likely to survive and pass those cognitive traits to their children. Empathy, then, may be a form of hunger. A similar tension runs throughout Fathoms: we are so often awed and enchanted by the lives and minds of other sentient creatures, yet we relentlessly try to consume and control those same creatures. Giggs is continuously haunted by our capacity to destroy what we cherish — by “the harm we and our kind have caused, but have failed, until now, to see.”

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Fathoms: The World in the Whale is so wide-ranging and multidimensional that, at times, some sections may appear to stray too far from the central subject. But this misperception evaporates if the reader remembers one of the book’s major themes: the wondrous and terrifying interconnectedness of our world. Rebecca Giggs is not strictly interested in whales in and of themselves, but rather the whale as a node: one of many points of connection in a vast and knotty ecological web whose ever-shifting fibers we are still tracing, even as we inadvertently shear them. Again and again, Giggs discovers that the lives and histories of humans and whales — our bodies and minds, our songs and diets — are linked by many more threads than one would expect, laced through time and space like so much transparent fishing line. After 9/11, she explains, American and Canadian authorities temporarily suspended nonessential shipping and boating and closed many ports to anything beyond small-vessel traffic. The soundscape in waters off the east coast of North America changed almost overnight as the usual background drone of giant ships dissolved into a relative sea of tranquility. Whales were free to communicate and navigate with much greater ease. When scientists analyzed fecal samples collected from North Atlantic right whales in the Bay of Fundy in September 2001, they found that their levels of stress hormones had dropped dramatically. What might seem like an entirely human concern can have consequences that ripple far beyond our ken.

“In their breadth of connectedness, do whales not show us how to be conscious of environments we ourselves cannot see, environments beyond our habitation where crisis is being staged?” Giggs writes.

To protect any wild animal now, the task is not to look for it, but to consider what it might depend on: the abundance of food, of shelter and paths of migration, the preservation of biophony, of oceanic chemistry and temperature within ranges tolerable to species other than our own.

Although this perspective might seem overwhelming to the point of paralysis, Giggs ultimately finds it empowering. When faced with planet-sized problems like climate change and mass extinction, it is easy for an individual to feel irrelevant and helpless, but the truth is that everyday choices — using a canteen instead of a plastic water bottle, purchasing a greenhouse tomato in winter — do have global significance.

A whale shows us it is possible to care for that which lies outside our immediate sphere of action, but within our sphere of influence — we care deeply, you and I, about the whale because it is distant. Because it speaks to us of places we will not go. Because it magnifies the reach of our humanity, and reminds us of our collective ability to control ourselves, and of our part in a planetary ecology.

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Ferris Jabr is a contributing writer for The New York Times Magazine. He has also written for The New Yorker, Harper’s Magazine, The Atlantic, and Lapham’s Quarterly. He lives in Portland, Oregon, where he is currently working on a book about the coevolution of life and Earth.