To fascinate us, sperm whales do not require vengeful tempers, like that possessed by Herman Melville’s fictional white leviathan, Moby Dick, though some controversial new research suggests they may indeed have a mean streak. Their swollen, gourdlike heads contain the planet’s largest brain and a prodigious reservoir of once highly prized spermaceti. They can plunge 3,000 feet below the ocean’s surface in grand hour-long dives to feast on, among other things, giant squid, which are believed to use their sharp parrotlike beaks to gouge the whales’ snouts in death matches in the deep dark. Ambergris, a golden material treasured by beachcombers since ancient times and used in perfumes, grows only in the gut of the sperm whale. And then there’s the tale of the Essex, a Nantucket whaling ship whose spectacular demise in 1820 inspired Melville 31 years later to send Captain Ahab and the Pequod to their epic doom.
While hunting in the equatorial Pacific, the Essex crew encountered a sperm whale bull some 85 feet long and weighing about 80 tons. It faced the ship, spouted from its blowhole and charged, its forehead breaching the swells and its great flukes thrashing the sea to white water. The collision shook the 238-ton vessel and sundered its oak-and-copper hull. After the beast swam off, "not a word was spoken for several minutes by any of us," the first mate recalled in an 1821 book. "All appeared to be bound in a spell of stupid consternation." Of the 20 men aboard, 12 perished trying to reach South America, 1,800 miles away, in the Essex’s small boats. They had steered south and east, rather than west toward the nearer Marquesas Islands, partly out of fear of cannibals—though, ironically, some Essex sailors ended up eating dead crewmates to survive.
The story of the whale attacking with "fury and vengeance" in its eyes, as the first mate put it, has long fueled speculation and debate about the animal’s nature, especially its enormous noggin: Why so big? Melville, inspired by the Essex tale, implied that it was a battering ram. "It is as though the forehead of the sperm whale were paved with horses’ hoofs. I do not think that any sensation lurks in it," observes Ishmael, Moby Dick’s narrator. But modern experts say that sperm whales, despite one or two notorious incidents, generally don’t attack boats or anything else. Instead, they say, the mighty whale reigns as a gentle giant of the sea.
Now that view is being challenged by a team of biologists at the landlocked University of Utah. David Carrier, the group’s leader, usually studies locomotion among land animals and doesn’t claim to know much about marine mammals. "I’ve never even seen a sperm whale," he admits. But after reading Nathaniel Philbrick’s 2000 book about the Essex tragedy, In the Heart of the Sea, Carrier wondered why evolution had apparently endowed sperm whales with the heady wherewithal to sink a ship.
Carrier and coworkers speculate that male sperm whales use their heads to batter rivals while competing for females—behavior, they point out, common to humpback whales and bottlenose whales. Sperm whale bulls are loners that rove equatorial waters in winter searching for a pod of females with which to mate. To succeed, they must fend off other males, for which, say the Utah researchers, their anatomy seems ideally suited. The male’s huge forehead is rugged, padded with tough skin and blubber, and the brain is located many feet back, as if for safekeeping. Six fused-together vertebrae, Carrier says, act as additional shock absorbers.
He acknowledges that the evidence for butthead sperm whales is less than perfect. He did not examine live specimens, and only a few observers—sailors—have claimed to see the great creatures dueling. Instead, his theory is based on comparisons with other cetacean species whose males battle for multiple mates; on mathematical models of sperm-whale collisions; and on evidence such as the extensive scarring found on sperm whale bull foreheads.
But some whale experts view Carrier’s theory, presented in the June issue of The Journal of Experimental Biology, as so much blubber. To be sure, researchers don’t know the exact function of the sperm whale’s outsize head. Some emphasize its role in echolocation, a sonarlike navigation system. Some suggest it functions as an amplifier that magnifies sounds—the loudest recorded from any animal—to stun giant squid and other prey or communicate with other sperm whales.
Some experts say Carrier made mistakes typical of a landlubber, confusing the animal’s melon, an oil-filled section of the head found in other toothed whales, with its spermaceti organ, unique to sperm whales. Bertel Moehl, a cetacean expert at Denmark’s University of Aarhus, laments that Carrier has advanced such a different view of sperm whale behavior with what he says is scant evidence. Hal Whitehead, a sperm whale expert at Dalhousie University in Halifax, Nova Scotia, dismisses the new idea, saying that if the male sperm whale’s disproportionate head evolved to attack other males, then "natural selection was very remiss in giving the females one too." Ted Cranford, a San Diego-based whale expert, criticized Carrier for not directly studying sperm whales and ignoring previously published data that don’t fit his theory.
But other cetacean experts, like the Smithsonian Institution’s James Mead, say Carrier’s theory is intriguing and worthy of further study. Carrier, for his part, says that he and his team have merely revived an old theory that scientists abandoned long ago. If the Utah researchers are right that sperm whales are built for aggression as Melville fantasized, the sea will lose a gentle giant. But it would prove that science, like life, can imitate art.