We owe them an apology.

I saw my first whale in a safari park outside London—a captive orca named Ramu—back in the early 1970s. As it ran through its routine, it was clear to me, even then, that this wasn't the right way to keep a wild animal. That much was clear from the way the whale's huge six foot dorsal fin had flopped over—a detumescent symbol of its emasculated state.

Since the 1960s, 200 killer whales have died in captivity. As the recent death of an orca trainer in Seaworld shows, our interface with whales seems destined to be troubled, and certainly exploitative—sometimes in unusual ways. In Australia in the early 20^th century, shore whalers at Eden, on the coast of New South Wales, co-operated with a pod of orca led by a bull male named Old Tom. The killer whales—so-called by early hunters because they saw these whales killing their own kind—would herd humpbacks passing by on their migration south toward the Antarctic. The orca would corral the unsuspecting great whales into the cup of Two-fold Bay. There the human hunters would row out to harpoon them.

As the carcass sank to the shallow sea bed, the orca would be allowed to claim their part of the bargain: the humpback's tongue, the only part of the animal they relished. Twenty-four hours later, bloated with gas, the dead humpbacks would rise to the surface for collection by the whalers. Eden, whose bloody waters were so ill named, was a cynical exploitation of two species of cetacean. The truth is now, as it's ever been: We need whales more than they need us. Once we hunted them for their industrial resources. Now we demand to be entertained by them. What they want, most probably, is to be left alone.

The whale is an animal characterized by an exquisite paradox. It is the largest, loudest, longest-lived creature ever to exist on our planet. Yet it is elusive, and for all its magnificent bulk, barely seen. Glimpsed in the water, it presents only a tantalizing jigsaw picture of itself: a fluke here, a fin there, a head or a snout.

It is telling that the leviathan's massive bulk is announced by an airy cloud of spume; that same sign may be all the fervent whale-watcher will see of his or her prey. Since time immemorial, the whale has been wreathed in mystery—and of course it almost predates time itself, having existed long before the land around which it swims.

"We account the whale immortal," Herman Melville wrote in the ur-whale text, Moby-Dick.Yet even as Melville published his book, in 1851, it would take another century for humans to film the whale in its natural habitat. We knew what the Earth looked like from outer space before we knew what the sperm whale looked like underwater. As Ishmael notes, "the living leviathan never fairly floated itself for its portrait."

It is this essential mystery that leads us on in our conflicted attitude toward cetaceans, named for the Greek for sea monster. Theirs is a discrete, multifarious suborder of mammals, one that comprises the now-extinct archeocetes; the mysticetes (moustached) or baleen whales; and odontocetes, or toothed whales. They total some 85 species in all—maybe more—and are ranged in every waterway around the world, from the tropical Amazon to the frozen Arctic, from the wide Pacific to the narrow Mediterranean Sea.

Eminently adaptable in a manner that perhaps only Homo sapiens can mimic, cetaceans inhabit much more of the globe than we do. Our puny existence is limited to the two-dimensional land, mortally bound by gravity. They live in three dimensions, free to wander at will, in an environment whose mass far exceeds our own earthly and tentative plane.

The whale is a remarkably recent addition to our anyway limited knowledge of the natural world. Indeed, we are only beginning to understand its nature even as it slips away from us. During the five years it took to research and write my book, The Whale, one species of cetacean—the Yangste River dolphin—went extinct, while one new species, the Australian snubfin dolphin, has been identified.

This sense of revelation is in part due to our changing attitude towards the whale. The monster of Biblical myth and medieval legend—the horned beast spouting in the remotest seas, at the edge of the known world—became an industrial resource in the modern era, hunted for its light-giving oil. (It is another essential irony that the unit of light itself, the lumen, should be measured from spermaceti candles provided by an animal that spends most of its existence in the darkest profound of the ocean.)