Leviathan or The Whale

tendency to foregather when endangered, and destroyed entire schools ‘by dextrous management’. ‘They did not swim away or dive,’ wrote an observer of a twentieth-century hunt. ‘The gunner, therefore, took the whales very easily, starting with the largest one.’ As Beale adds, poignantly, ‘The attachment appears to be reciprocal on the part of the young whales, which have been seen about the ship for hours after their parents have been killed.’
    To humanize the whale oversteps boundaries; but when entire families follow a stricken relative to strand on a beach, or when a wounded female, mortally gashed by a ship’s propeller, is borne up by the shoulders of her fellow whales, it is difficult to resist the pang of emotion. They are truly gentle giants: as elephants are supposed to bolt at the sight of a mouse, so sperm whales can be faced down by a pod of militant dolphin. The appearance of a seal, or even the click of a camera, may send them scurrying. It is almost as though, as Dr Whitehead remarks, the whale sees its own habitat as a dangerous, even frightening place.
    Yet these are carnivorous animals, voracious in their appetites. They eat mostly cephalopods, but also take tuna and barracuda; entire thirty-foot sharks have been found in their bellies. And they consume in enormous proportions, taking from three to seven hundred squid a day: worldwide, sperm whales eat one hundred million metric tons of fish a year–as much as the annual catch of the entire human marine fishery.
    Diving deeper than any other mammal, we simply do not know how sperm whales behave in the ocean’s depths. We know what they eat, because we find it in their stomachs; but we don’t know how it gets there. Sound is certainly important to their sustenance. Although they lack a voice box–as Thomas Beale noted, ‘The sperm whale is one of the most noiseless of marine animals…it is well known among the most experienced whalers, that they never produce any nasal or vocal sounds whatever, except a trifling hissing at the time of the expiation of the spout’–the whale possesses the largest sound system of any animal, using one-third of its body to create the loud clicks that it constantly emits when hunting. The whale’s oversized nose is in fact a huge and highly efficient squid-finder.
    As bats send out sonar to find flying insects, so sperm whales send out similar, if rather louder, pulses to locate their prey. Their characteristic clicks are produced by the expansion and contraction of ‘blisters’ on their nasal sacs. It is a remarkably complicated sequence, as Dr Whitehead explains. Two nasal passages run from the external blowhole, the left and the right. The left runs directly to the lungs, but the right passes through a distal air sac via a kind of valve known as the
museau du singe
, or ‘monkey’s muzzle’.
    Sound is initially generated by air being forced through this valve–not unlike the clicks you can make by hitting the roof of your mouth with your tongue–then passes through the animal’s upper spermaceti organ or ‘case’ before bouncing off another, frontal air sac set at the back of the skull–a bony sound mirror, in effect. This is then redirected and broadcast through a series of acoustic lenses in the ‘junk’, the lower oil-containing organ in the whale’s head. Thus the strange mechanism of the sperm whale’s nose acts as a living amplifier. Some sound also bounces back and forth along the case, producing a second pulse. As this inter-pulse interval is equal to the length of the case, the actual sound created by the whale–the pulses between its clicks–may be a measurement of its physical size; one may tell the length of the animal from the inter-pulse interval, just as the bigger the whale and its head, the more powerful its clicks. Breeding males may size each other up from their clicks, and can tell each other’s sex by the same sound; they are as much a tribal definer as the click speech of the Xhosa of South Africa.
    The clicks, which can be heard for many miles, are important for navigation and communication. They extend the whale’s sensory map far beyond its own body, and their speed and variation change from group to group, as an English dialect changes from Yorkshire to Hampshire. This allows individual whales to identify and communicate with members of their family, evenas they use the earth’s magnetic fields to map out their subaquatic terrain, the peaks and