Bump, bump, bump. An inquisitive orca repeatedly banged its snout against the hull of an acquaintance’s sailing boat during his recent trip around Scotland. In the same waters, I met a minke whale. Unaggressive, unafraid, it stuck one side of its prow-like head out of the sea to survey the people on deck.

During such alarming or captivating encounters one always wonders the same thing: what is it thinking? These animals are smart. But what you see in the eye of a wild cetacean, no matter how intelligent, is a human being, reflected back. Books about whales are another mirror. Rebecca Giggs, author of Fathoms, is the latest contributor to the genre.

Giggs analyses her thoughts about her subject extensively. It is a style of writing that suits our self-absorbed age. Back in the Bible-bashing 19th century, Herman Melville saw the leviathan as a symbol of divine predestination. In the new-agey late 1980s Heathcote Williams’ Whale Nation extolled whales as wise superbeings.

The experiences Giggs describes are hardly exceptional. She goes on a whale-watching trip from New England as so many have done. She eats minke whale in Japan (I declined to, but I wasn’t writing a book). She reads whale literature and interviews experts. More impressively and movingly, she describes watching a stranded humpback dying on an Australian beach.

Another bystander tries to place a wreath on the whale as it succumbs to heat stroke and the crushing effects of gravity. A wildlife officer administers a lethal injection.

That is the problem. We humans cannot help interfering in the lives of what biologists call “charismatic megafauna”, and fauna does not come any more charismatic or mega than whales. But practically all our impacts hurt them. Icelandic and Japanese ships still pointlessly slaughter whales for their unpopular meat. Intrusive whale watchers harass them. I once saw a thoughtless speedboat jockey drive a grey whale and her calf apart off the coast of California. Whales cannot even feed naturally in oceans awash with plastic rubbish.

As for Melville, he spent a year and a half as a sailor aboard the Acushnet, a New England ship that harpooned whales, chopped them up and turned them into oil for lighting and lubrication. His epic novel Moby-Dick is a difficult read these days. Not only does it mythologise an industry now regarded as repugnant, but the Polynesian, Native American and African whalers who are its human heroes are presented as stereotypes of the noble savage — and the book is much too long.

Yet Moby-Dick remains one of the greatest books ever written about an animal. The awe that Melville felt hunting sperm whales — tough, social, deep-diving predators — was only increased by the possibility that one of them might kill him.

Philip Hoare’s Leviathan, published in 2008, is the best starting point for readers interested in Melville and the whale lore to which he contributed. He describes, for example, how scientists who had never seen sleek blue whales in the water built the portly replica in London’s Natural History Museum.

Nor, despite her book’s title, does Giggs quite fathom the whale, an animal whose life is so unlike our own. No shame there. Even Melville confessed that he did not really understand these creatures, despite writing 200,000 words inspired by them.

What we do know is that if cetaceans are in trouble, so are we. The hubristic slaughter of the great whales from New England presaged a broader collapse in biodiversity. Moby-Dick’s modern counterpart, as human degradation of the planet accelerates, is a whale whose stomach is stuffed with discarded plastic.

Fathoms: The World in the Whale, by Rebecca Giggs, Scribe, RRP£20, 358 pages

Jonathan Guthrie is head of Lex

Join our online book group on Facebook at FT Books Café

Listen to our podcast, Culture Call, where FT editors and special guests discuss life and art in the time of coronavirus. Subscribe on Apple, Spotify, or wherever you listen