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Thursday May 13th, 2021
Environment

Ahab’s Nemesis: Sri Lanka may be the best place in the world to see sperm whales

 

Does Melville intend this particular irony? Sure, in Captain Ahab’s vengeful fantasies, the weirdly white sperm whale who swallowed his leg seems to embody pure evil, while for narrator Ishmael, Ahab’s obsession with slaying his nemesis may itself be evil incarnate: arrogant humanity exterminating ‘innocent’ nature.

But does Melville- seasoned sea goer he -know something of sperm whale temperament that his character Ahab does not? Melville’s main scientific source, Thomas Beale’s The Natural History of the Sperm Whale, refutes allegations of bloodthirstiness, but Moby-Dick makes much of the creature’s bad reputation in the tales and legends of whalers.

Ex-pat amateur naturalist Gehan de Silva Wijeyeratne convincingly suggests that Sri Lanka may be one of the best places in the world to see sperm whales. Even more interesting, he musters evidence that Lanka may be the best place in the world to see sperm whale ‘superpods’—dozens of the awesome beasts assembled and visible at the same time.

A super-pod off Kalpitiya in early 2010, for example, numbered some 60-70 animals, according to Navy sources. A gathering off Trincomalee in March 2012 may have numbered up to 250, as experienced observers estimated. Comparing such sightings with those elsewhere, Wijeyeratne nominates Sri Lanka as world capital in terms of super-pod frequency, density and viewability.

At seventeen pounds, the sperm whale brain is the largest of any creature ever: evidence of high intelligence. She scores high in sociability as well. We understand more and more that high intelligence in vertebrates correlates with high sociability. Nimbleness in navigating complex social spaces requires, rewards and nurtures braininess.

In Leviathan or, The Whale, Philip Hoare contends that sperm whales “have the most complex social structure of any animal other than man.” He does not explain how he reaches that conclusion or by what criteria, but he does offer some detail.

Like elephants, sperm whales typically move in clusters of juveniles and mature females, who share in care for the young. When mother dives for food, she leaves her calf for her cluster to babysit. Networks of trust, communication and exchange of favours must be dense. Neuronal connections likewise, very likely.

When orcas (killer whales) threaten, sperm whales encircle their young in cooperative formation. They may face inward, presenting a firing line of powerful flukes outward against assailants, or they may face outward with their dangerous toothed jaws. They will protect each other and each other’s young even at high peril to themselves.

Entire families have been known to strand themselves on beaches so as to keep company with a sick or injured relative. Different pods use different ‘dialects’ of sounds to communicate with each other. Here again, sperm whales are ‘elephants of the sea.’

Sperm whales eat mainly cephalopods (squid), which they find at sometimes incredible depths. Because she spends far more time below the surface than on it, one authority calls her a ‘surfacer’ rather than a ‘diver.’ But she has to breathe of course. Before a deep dive, she may hyperventilate, taking sixty breaths or so in ten minutes (very fast for her).

Her blood features stupendous oxygen-carrying capacity, enabling her to stay down for as long as two hours without surfacing. A dive of 500 metres is routine and she can go as deep as two kilometres or even more.

She feeds in the deepest darkness and crushing pressure from the water above. Though classified as a predator, of course, she has little of the classic hunter in her. With one or two possible exceptions detailed below, she has no need for the adrenaline-fueled savagery of bears, big cats, sea lions and the like for chasing and ripping up prey.

Sperm whale stomachs often contain large squid ingested whole with nary a mark on their bodies. It is thought that she simply sucks her meals into her huge jaws or perhaps just opens her mouth so that they swim into it. Some even think she stuns her prey with deafening bursts of sound. She gulps down maybe 600 squid daily, finding her prey by echolocation, like bats.

Emitting loud clicks, she ‘sees’ other creatures as well as seafloor contours from rippling wrinkles in the rebounding sound. Sound is her only useful sense in the depths she prowls, except for her sensitivity to the earth’s magnetic fields, useful for navigating long ocean journeys.

Because they spend so much time beneath the surface in the open ocean far from land, we know very little about sperm whales. Their first-ever underwater footage, taken in Sri Lankan waters as it happens, came only in 1984. No one can confidently say what they are up to in their frequent gatherings around the island.

They engage in a repertoire of colourful behaviours: jaw clapping, tail elevation, tail slapping, belly-ups, roll-overs, head raises and breaching—flinging themselves largely out of the water. An intriguing possibility raised by Cinnamon group ecotourism chief, Chitral Jayatilake, is that they may sometimes be flirting and be here mainly for that reason.

Sperm whales are classically ‘dimorphic’ between the sexes, meaning that mature males grow substantially larger than mature females. Males may measure twenty metres and weigh fifty tonnes. As with other dimorphic mammals, mating opportunities accrue overwhelmingly to alpha males who dominate their competitors in contests of strength and aggression.

In what naturalist Howard Martenstyn calls ‘harem formation,’ he keeps his weaker competitors away from his eligible females. Those females may in turn compete for his attention with some of the behaviours mentioned above. Again, it is possible that sperm whales congregate around Sri Lanka for the explicit purpose of mating.

Male-on-male competition is of course one arena where sperm whale behaviour is far from docile. Many males exhibit injuries from fights with rivals. Feeling hunted is another scenario that may bring out aggression. It is hardly surprising that whalemen stories selectively highlight aggressive behaviour.

Sperm whales dislike being chased and will flee or turn ornery when closely pressed. Almost certainly, there are sperm whales alive today with memories of being hunted and of seeing the slaughter of family and companions. Humankind is of course by far the most devastating menace sperm whales ever have faced.

No other adversary could by itself have pushed them to the brink of extinction. Orcas, to be sure, can seize juvenile or ailing sperm whales, so perhaps should be deemed more ‘apex’ as predators. Fearsome as they are, however, orcas may not be even the second-most-horrifying adversaries sperm whales have encountered in their day.

Old-time whalers told tales of sperm whales grappling in the writhing, sucking limbs of what may have been colossal squid. Perhaps someone picked the wrong item for lunch? On Animal Planet, I have seen human divers wrestling with giant squid: furiously fast, agile, deceptive and aggressive with their clinging, squeezing arms and tentacles. It can hold you down till you drown.

Her colossal cousin, rivalling sperm whales in length, might pose serious danger, though the reverse is also true. Hoare recounts one reported sighting of a sperm whale, dangerously entangled, calmly chewing her way out through a massive squid. But the whales may not win them all.

Sperm whale lacerations memorialize wounds from the hooks in colossal squid limbs. In Antarctic waters, three-fourths of sperm whale diet may come from colossal squid: one prey they really might need to rip up in order to eat. Whether this colossal sometimes, in turn, consume sperm whale is unknown since the squid rarely surfaces from their abyssal haunts to have their stomachs examined by captors. My guess is that both species dine on juveniles of the other.

More cryptic still, ‘sea serpents’ may be (or may have been) the sperm whale’s most fearsome non-human foe. Though unconfirmed through physical remains, sea serpents—dozens of metres in length, swimming sinuously, their heads high above the waves—have been reported by sea goers and seaside dwellers for centuries. Maybe these observers were mistaken, but they were not all crazy or drunk.

As for nonexistent physical remains, recall the adage: the absence of evidence is not evidence of absence. Hoare records multiple eyewitness reports of such creatures coiled double and triple around huge sperm whales. It sounds like a squeezing death, a la anaconda, perhaps joined with drowning.

It is conceivable that such ‘serpents’—with whales as their main prey?—have gone extinct due to whaling or other human causes before their existence could even be ascertained. As Shakespeare’s Hamlet (one of Melville’s favorites) puts it: “There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.”

(From the archives of Echelon magazine: first published in May 2015)

 

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