The Sea Inside

cetaceans can be given an overdose of horse tranquilliser which swiftly inhibits respiration and causes death. But for these leviathans, there is no such mercy. ‘It would be impossible to get enough quantities of the drug to euthanise a sperm whale,’ says Rob Deaville, ‘and even if we could, I doubt we could inject it.’
    The theories surrounding strandings are dizzying in their claims and counterclaims. Some focus on the whales’ ability to follow geomagnetic lines laid down in the earth’s crust. Such sensitivity – via minute magnetic cells that spin like internal compasses – has been detected in organisms from bacteria to birds. Birds in particular are thought to possess photopigments in their eyes known as cryptochromes that detect the magnetic field chemically, seeing it as a pattern of colours or lights which enables them to navigate. Could whales ‘see’ these same patterns? Some studies of the British coast, where the geomagnetic contour lines run parallel to the land, have suggested that whales move along ‘geomagnetic valleys’, and that where such valleys lead inland, strandings may occur.
    Others speculate that cetaceans set their ‘travel clocks’ by detecting these minute changes in the geomagnetic field; or that the circumstances for strandings may be created by sunspots known to affect the earth’s magnetic field, most visibly in the aurorae borealis and australis. Even more radical hypotheses suggest that cetaceans display a foreknowledge of seismic shifts in the earth’s surface, as if they were canaries warning of disasters as yet undetected by humans. The fact that recent major earthquakes in Japan and New Zealand were preceded by mass strandings of pilot and melon-headed whales seems to support this notion. But if we were ever able to lock into the magnetic fields that surround us, and that guide storm petrels and sperm whales alike, we lost the ability long ago. Our senses are sadly lacking, even in the three dimensions we purport to perceive.
    Out in the mid-Atlantic, we spend hours searching for sperm whales. ‘They’re acting weird today,’ says João, ‘playing games with us.’ We’re about to turn back when a pod of Risso’s dolphins appears out of nowhere.
    I’ve only ever seen these animals from afar. Now they’re just off the bow. Scarred and scratched, they resemble damaged ghosts, caught out of the corner of the eye. They even behave differently from other dolphins, staying shyly below the surface. Only as they come closer can I see their blunt snouts and high dorsals, their flanks graphically black and white, like psychedelic zebras. Antoine Risso, a French contemporary of John Hunter’s with a particular interest in crustaceans and copepods, lent his name to these animals. In the Azores they are known as
moleiro
, for their whiteness.
    Sliding over the side of the boat, I see their shapes moving below me in the gloom. Through the water I hear them singing
–
a sweet, high-pitched song rising up from these cetacean choristers in the sea’s cathedral. Melville does include them in his Cetology, although whether he ever saw one is uncertain: ‘Though this fish, whose loud sonorous breathing, or rather blowing, has furnished a proverb to landsmen, is so well known a denizen of the deep, yet is he not popularly classed among whales. But possessing all the grand distinctive features of the leviathan, most naturalists have recognised him for one … By some fishermen his approach is regarded as premonitory of the advance of the great sperm whale.’
    As they rise to the surface, their enormous dorsals appear, enough to identify them even without a glimpse of their battle-scarred backs, which resemble those of beaked whales. I peer at them through my mask; to see these cetaceans so close and yet so elusive only makes them seem more particular.
    Back on shore, Karin Hartman, a Dutch scientist studying Risso’s dolphins, tells us a little more. She says the males are whiter than the females, partly because they fight more and find more squid, leaving their scarred skin unpigmented. The paler they are, the more attractive they are to the opposite sex, as good foragers and representatives of a tough and frisky breed. ‘It’s sexy to be white,’ says Karin. The whitest are also the oldest, since their skin becomes thinner as they age.
    As with other whales, this ratio of dark and light is an advertisement of their individuality. Yet like sperm whales and