The Sperm Whale's Deadly Call | Science | Smithsonian
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Whalers pursued sperm whales for the rich oil in their oversized heads. Now biologists are on the tail of these deep-diving, long-lived, sociable and mysterious sea creatures. (Gerard Soury / Oxford Scientific / Getty Images)

The Sperm Whale's Deadly Call

Scientists have discovered that the massive mammal uses elaborate buzzes, clicks and squeaks that spell doom for the animal's prey

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On the swells of the Sea of Cortez, everything looks like a whale. But the suggestive shapes usually turn out to be whitecaps or a cloud’s shadow. Lulled by disappointment, the rocking boat and general monotony, I drift into torpor. Then, less than half a mile away, a series of unmistakable spouts erupts, and bursts of exhalation carry across the water.

The BIP XII, a trawler from Mexico’s Center for Biological Research, changes course and chugs toward a group of about 25 sperm whales—adult females, juveniles and suckling calves up to 2 years old. The calves and juveniles are 15 to 20 feet long, and some of the larger females are more than 30 feet from head to tail (a male would be almost twice as long). We approach one that appears to be sleeping, its rumpled back and bulging head rolling with the waves. It snorts awake and swims off as its companions drift away from us in loose pairs and trios. We trail after one of the pairs, a female and calf. The two idle along, nudging each other and blowing mist. Then the female surges forward. The huge muscles of her flanks go taut as she arches her back and heaves out her tail. Water cascades off her broad tail flukes, and she dives. The calf follows, Leviathan in miniature, its flukes aloft as it slides into the sea.

The other whales start to dive and our boat slows to a stop. The 12 of us aboard, a mix of biologists and crew members, gather at the rail to await the whales’ return. Five minutes turns into ten, then fifteen. Still they do not surface. We have a schedule to keep and so must motor on.

The life of a sperm whale remains largely a mystery. The animals spend most of their time at great depths, diving more than 6,000 feet in pursuit of prey and staying down for more than an hour. They are the largest toothed whales (a few filter-feeders, like the blue whale, are larger) and can grow to more than 60 feet long; their brains are larger than those of any other animal on earth. But even after decades of study, basic elements of sperm whale biology and behavior are poorly understood. I am here because scientists have started to figure out just what it is a sperm whale does in the deep: how it hunts, how it communicates, what it might be saying. From the boat’s stern, I look back at the patches of water, now still, where the whales had been, and presumably still are, somewhere beneath us.

Until recently, most information about sperm whales came from their slaughter. In 1712, so the story goes, one Captain Hussey’s vessel was blown offshore south of Nantucket Island while hunting right whales for their oil. Hussey happened upon a pod of sperm whales, killed one and dragged it home. The animal’s huge head brimmed with a peculiar waxy substance, called spermaceti (“seed of the whale”) after the mistaken belief it was seminal fluid. Spermaceti oil was versatile, and of a much higher quality than oils that came from the blubber of other whale species. As a liquid, it fueled lamps; congealed, it could be fashioned into smokeless candles, fine soaps and cosmetics. Hundreds upon hundreds of ships from North America and Europe were soon plying the world’s oceans in search of sperm and other whales.

“Whaling was the oil industry of its day,” says Hal Whitehead, a biologist at Dalhousie University in Nova Scotia and an expert on sperm whale behavior. “Oil from the sperm whale quite literally lubricated the Industrial Revolution.” At the revolution’s height, in the mid-1800s, whalers killed perhaps 5,000 sperm whales a year.

The industry captured the popular imagination. “Old-time whaling had a dual identity,” Whitehead says. “It was a way of getting stuff we needed, but it was also a wild, romantic chase. A lot of art was linked to the sperm whale.” But the need for spermaceti decreased with the drilling of petroleum and natural gas wells and the harnessing of electricity. By the 1880s, whaling’s early phase was on the decline.

The reprieve would last until 1925, when “factory ships” set sail from Norway, bristling with harpoon guns and designed with slipways for sailors to haul whales aboard for quick processing. A whale once sighted was effectively dead. The factory ship’s speed and artless efficiency made whale hunting cost-effective. Whaling would increase significantly after World War II, and by 1958, more than 20,000 sperm whales were killed each year to be turned into margarine, cattle fodder, dog food, vitamin supplements, glue, leather preservative and brake fluid. The global population of sperm whales and other whale species declined so drastically that in 1982 the International Whaling Commission, a body established in 1946 to monitor whale populations, issued a moratorium on commercial whaling. It’s hard to count such an elusive species, but Whitehead estimates that before com­mercial whaling began, there were more than one million sperm whales. Now that number may be around 360,000, and it’s unclear whether the population is increasing.

The ban improved human-sperm whale relations but made the study of whales more difficult. Whaling gave scientists access to otherwise inaccessible subjects, but yielded reports that tended to emphasize the animal’s physiology and diet rather than behavior. One researcher speculated that based on the properties of oil at different temperatures, the spermaceti organ helped regulate buoyancy; others combed through the stomachs of dead whales, counting squid beaks to see which species they liked to eat. From a boat like the BIP XII, all one can see of a sperm whale is the tail and the broad slab of back and head that rides above the waves. Less than 10 percent of a whale’s body is visible, in a part of the ocean—the surface—where the animal spends less than 20 percent of its life.

Sperm whale research now relies more on technology and an ability to think like a leviathan. “We have a very mysterious animal that we don’t understand,” Whitehead says. “Sperm whales live in an environment totally different from ours, one with completely different constraints. Where we are visual, they see the world through sound—both the sounds they hear and the sounds they make.”

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