Then, etched at the edge of visibil­ity, the first black-and-white heads appear, darting towards me, peeling off at tangents, transforming the wa­ter into an animated labyrinth of sleek striped bodies.

Drawn by their tightly choreo­graphed dancing I dive down, twist­ing and spiralling in imitation as they circle around me, tilt their heads and level their large black eyes at mine.

A trio of quivering beaks emit a cascade of clicks which scan the sur­rounding ocean, speeding up as they zero in on my body. I revel in the blast of white noise that crackles like an excited Geiger counter, sensing the hollow cavern of my lungs and the solid orb of my head.

I have entered their world, an acoustic universe as sensitive and nuanced as ours is visual. Here a dolphin’s head acts as a living sonar system, a kind of ultrasound scan that sends out simultaneous signals on different frequencies, and enables the animal to build up an acoustic map of its environment, communi­cate with the rest of the group and, possibly, stun its prey.

I call to them through my snorkel. What they make of such garbled sound I don’t know, but the more inquisitive ones begin to sprint in tight circles, forcing me to spin on my axis to keep eye contact. They are so close now I can reach out and touch them, each one unique down to the nicks and scars on its fins.

My lungs ache for air, and the pod of duskies begins to move away. I long to swim after them, deeper into that emerald city, but there’s an ur­gent oxygen debt to be paid at the surface. I burst back into the sunlight, suck in a deep breath and look around. Nearby, watching from his runabout, is skipper and local tour operator Brent McFadden; in the dis­tance, the duskies’ curved backs are rhythmically cresting the swells—a gentle finale to today’s mercurial “symphony of the dolphins.”

Kaikoura is dolphin Riviera. Here nutrient-rich water from the South­ern Ocean rises close to shore, sup­porting massive plankton production and offering a banquet of kahawai, mackerel and squid to the cetaceans (whales and dolphins) which gather offshore.

Here the commonest cetacean spe­cies, and the most acrobatic, is the dusky dolphin. Duskies are southern hemisphere dolphins which frequent areas that are cooled by circumpolar currents: the southern tips of America, Africa and Australia, as well as New Zealand from East Cape southwards. They are medium-sized dolphins—up to two metres in length—and have particularly strik­ing faces: a short thick black snout, grey-black eye patch and mouths that look like a pair of smiling pursed lips pushed up towards the eyes by the neat symmetry of their white chins.

Like most oceanic dolphins, duskies feed co-operatively. As they travel, they scan the sea with their echolocation apparatus. When they find a school of fish or squid, they work together to corral the prey into a tight “meat ball,” before taking turns to move in and feed. Some individu­als patrol the perimeter of the school, leaping and belly-flopping and flail­ing the surface of the water with their tails to keep the school together. Oth­ers swim below, shepherding the school upwards and using the sea surface as a wall against which to imprison their prey. All the time the dolphins maintain a steady stream of clicks—the equivalent of keeping in radio contact with each other.

North American dolphin expert Professor Bernd Wiirsig has been studying Kaikoura’s dusky dolphins for 20 years, and has found that the animals follow definite patterns of feeding, resting and playing. Usually a short burst of intense feeding activ­ity in deeper water is followed by rest and play in the shallows, where it is easier to avoid attack from below by predators such as orca (killer whales) and sharks.

Much can be learned from the type of leaps the dolphins use, says Wiirsig. Clean, head-first re-entries and “body-slams” indicate feeding, but the highly acrobatic spinning leaps so admired by dolphin-watch­ers are reserved for playtime, when the dolphins have games of catch and toss with seaweed, interact with tur­tles or birds, or indulge in recrea­tional mating.

I see this behaviour for myself one morning at Kaikoura. On our way out to the feeding grounds we are met by a small party of five duskies knifing through the oily swell, their svelte forms silhouetted against the rising sun. Several males are courting a fe­male, amorously vaulting in synchro­nised arcs over her head, and often nearly colliding with each other in their enthusiasm. The female leads the group back and forth in a wide zig-zag path before choosing her mate; together the two glide down into the water, belly to belly.

Leaving them to their nuptials, we speed on to where a larger pod is feeding. A flock of terns wheel and dart overhead, picking up bait fish. I hang over the bow watching the wave-riders, their whistles clearly audible out of the water. In amongst the duskies I notice a group of common dolphins, easily identified by their distinctive bronze blaze and criss-cross markings. Sleek and stream­lined, with a long beak and tapered flippers, common dolphins are about the same size as duskies, but are usu­ally lighter (an average weight of 80kg as against 115kg). They have a thin black bridle running between black eye patches above the purple hue of the beak and lips. As their name implies, they have a world­wide distribution.

Two other boats pass us, loaded with eager dolphin swimmers. They are on a high, calling to the dolphins who seem to have brought out the child in us all. One curious dusky bobs up, half out of the water, “spy-hopping” for a closer look at the as­sembled flotilla, and is quickly met by a battery of camera shutters.

Dolphin encounters like these, once a fringe form of eco-tourism, have transformed Kaikoura into a backpacking boomtown. Since swim­ming permits were first issued in 1991, the demand for in-the-water dolphin contact has increased mark­edly, and this summer some 35,000 tourists—mainly young Europeans—have visited Kaikoura for the dolphins and whales.

Photographer and co­founder of Kaikoura’s Naturewatch Tours Barbara Todd began offering swims with dolphins at the request of her whale-watching cus­tomers. While agreeing that dolphins and humans seem to have a mutual fascination one for the other, she believes many people project their pre­conceptions on to dolphins—seeing their exuberant acro­batics as performances for their human audiences. Not so, says Todd. Leaping is as much a part of normal dolphin life as pronking is in antelopes, or frolicking in baby lambs. Todd herself prefers to think about the way dolphins may be re­garding us: “With our lifejackets and cameras we probably look to them like funny orange blobs, with one big eye that clicks.”

Todd has seen many unusual sights on the water: duskies playing with seals, sperm whales and other dolphins, and, most eye-opening of all, interspecies copulation between duskies and commons, and commons and bottlenose dolphins. (Successful mating between species has been re­corded in captivity, but, as with horses and donkeys that breed, the offspring are usually sterile.)

To human eyes, dolphins appear highly promiscuous animals. Adults do not form pair bonds, and even the very young members of a school prac­tise courtship and mating behaviour. Much of this activity appears to be non-reproductive, as it takes place outside of the peak period of concep­tion, and dolphin researchers con­sider it to be part of a continual proc­ess of building and maintaining com­munal relationships within the pod.

Dolphins have a low reproductive rate, usually producing a single calf every 2-3 years. Gestation lasts 10-12 months, and rearing up to two years. With a life span of around 20-50 years, dolphins bear their first calf between five and 12 years, depend­ing on the species.

Calves are usually born tail-first, with the mother biting the umbilical cord (if it hasn’t already broken) and helping the calf to the surface for its first breath. Dr Alan Baker, director of the National Museum and author of a dolphin identification guide for New Zealand and Australia, describes a typical birthing scene he observed in a common dolphin in the Bay of Is­lands: “There was a commotion in the water, with lots of spray and flap­ping, and about 20 attendant dol­phins whistling and standing guard around the mother.”

The presence of “midwives” is normal in dolphin society. They may physically support the mother from below if she is in need of help, and will often stay in attendance and “baby-sit” the calf while the mother feeds during the first few months af­ter the birth.

At Kaikoura, dusky dolphins be­gin to congregate in shallow inshore waters in mid-October, and give birth from November through to January. The mothers and calves break off from the main herd to form separate nursery groups which are matriar­chal—adult males appear to play no part in rearing. The primary bond in the herd is therefore between mother and young, the calf being dependent on her fatty milk during the 18 months to two years that it will spend in the nursery.

Calves stay close to their mothers for the first months of their life, swim­ming alongside and often touching them with a flipper. A mother will assist a distressed calf by supporting it with her head or back, and it is perhaps this nurturing reflex that is behind the many reported cases of dolphins assisting human swimmers in distress.

Sex and age segregation have been observed in a number of dolphin spe­cies, but generally dolphins live in mixed, fluid groups with no single leader, and different members take turns to steer the group’s course.

Common dolphins are a possible exception. This species, which may form groups of several thousand, is thought by some researchers to have a more defined hierarchy, with domi­nant animals defending vulnerable members and reproductive females.

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New Zealand’s well-placed slivers of land span subantarctic and subtropical latitudes and are home to 15 of the world’s 60 dolphin species, includ­ing both the world’s smallest and larg­est species.

As well as the demonstrative com­mon, bottlenose and dusky dolphins, there is the endearing Hector’s dol­phin (known only from New Zealand waters), the larger orca and pilot whales, and more obscure occasional visitors such as the Risso’s, hourglass, striped and spotted dolphins.

For most people, whether cruising in the Marlborough Sounds or fish­ing in the Hauraki Gulf, the most likely place to see a dolphin in the wild is riding the bow wave of a boat—an activity dolphins have been engaged in ever since there were bow waves to ride. Writing in his Historia Animalium in AD 70, the Roman poet Pliny the Elder attributes superhu­man speed and agility to the common dolphin: “It is swifter than a bird and darts faster than a javelin . . . They shoot up like arrows from a bow in order to breathe again .. . and leap out of the water with such force that they often fly over a ship’s sails.”

Herman Melville digresses from describing his Great White Whale to remark, “If you yourself can with­stand three cheers at beholding these vivacious fish, then heaven help ye; the spirit of godly gamesomeness is not in ye.”

The dolphins’ earliest aquatic an­cestors, by contrast, would have elic­ited few cheers. Palaeontologists be­lieve that the protodolphin was a derivation from wolf- and otter-like land mammals, and that it first took the plunge fifty million years ago, when much of the earth was covered with lush tropical swamp, and shal­low equatorial seas were advancing over the coastline. These archaeoceti, as they are known, had elongated bodies, long tails, reduced hindlimbs and paddle-shaped front limbs, but they were probably little more el­egant in the water than the plesiosaurs and icthyosaurs—marine dinosaurs—which had died out some 15 million years earlier.

Temperature changes in the world’s seas, continental shifts and the creation of the Antarctic circumpolar current all accompanied the  emergence of the primitive odontoceti or toothed whales (the group to which dolphins belong) as well as the larger mysticeti or baleen whales from this archaic group. Over time, the long mobile neck. hindlimbs and pelvic girdle of the archaeoceti receded in favour of a more streamlined body shape, dorsal fin and tail flukes.

Fossils of three living dolphin groups, the Delphinidae (true dol­phins), Phocoenidae (porpoises) and Monodontidae (narwals and white whales), show that today’s dolphins first appeared on the evolutionary stage around ten to fifteen million years ago, competing with giant pre­historic penguins and sharks for su­premacy as marine predators.

In common parlance, there is of­ten confusion between the names “dolphin” and “porpoise,” and many people use them interchangeably. Historically, porpoise comes from the French “porc poisson” or pig fish, while dolphin is from the Greek “delphis”, which means womb. (Dol­phins frequently appeared in Medi­terranean creation myths where, along with women and various “womb monsters,” they symbolised new life and regeneration.)

Biologists, however, distinguish porpoises from dolphins by the fact that they have no beak, are generally smaller and “chubbier” than dol­phins, and have fused vertebrae and spade-like, rather than peg-like teeth. Present-day dolphins’ speed and agility—all the more impressive when you consider that water is 30 times denser than air—has been achieved by superb adaptation to the aquatic medium. The skull has been telescoped to allow the jaws to ex­tend forward, and the nasal opening  has moved to the top of the head. Neck and shoulders have gone, and the flippers, which have a similar skeletal structure to the human arm, have paddle-shaped, flattened “fin­gers” for steering and stability. Hind limbs have all but disappeared, leav­ing a boneless and horizontal tail pro­pelled by four massive blocks of mus­cle. The similarly boneless dorsal fin provides stability and some degree of temperature regulation.

To further reduce drag, dolphins have lost all body hair, and external ears have been replaced by two minute open­ings on the side of the head, leading to the hearing organs.The teats and genitals have been similarly retracted inside muscular folds in the belly.

Because they feed on fast-moving fish and squid, dolphins must be able to shift from a cruising speed of around 9-17 kilometres per hour (5-9 knots) to chase speeds of up to 40kph (20 knots) over short distances, a feat often augmented by bow wave riding and repeated arcing leaps known as “running.”

Recent research in Hawaii has shown that dolphins may use bow wave riding as a kind of energy-effi­cient hitch-hiking. By keeping the body motionless and using the tail flukes as hydroplanes, dolphins are able to use the force of the wave to propel them with minimal ef­fort. Experimental results in­dicate that for the same en­ergy output, dolphins on a bow wave can double their normal cruising speed. (On the other hand, maybe they do it just for fun!)

The dolphin’s evolutionary redesign also extends to the skin and blubber. Living en­tirely in the sea, a dolphin might be expected to have a waterproof skin. In fact, it is waterlogged. And, unlike hu­man fat, the blubber is not rigidly attached to the underlying muscle. Like a living swimsuit, the dolphin’s skin is moulded by the water conditions to form small tem­porary ridges, dispelling turbulence and reducing drag.

Adult bottlenose dolphins can dive to 500 metres for up to seven minutes, while the largest dolphin, the orca, can go down to a kilometre. Being air-breathing mammals, dol­phins naturally have to hold their breath when diving, just as we do. This presents any mammal with a problem. Under the compression of a dive, the nitrogen in air dissolves into the body’s fluids and tissues. On the way back to the surface this dis­solved nitrogen may re-form as bub­bles in the tissues and blood, causing the potentially fatal condition called the “bends.”

Dolphins avoid this problem by absorbing and storing oxygen in their muscles while on the surface. They only dive with small amounts of air in their lungs, and the lungs collapse under the pressure of the dive, forcing the air into the ani­mal’s nasal passages where no nitrogen can be absorbed. Fur­thermore, the dolphin’s lungs are richly supplied with very fine capillaries, and it is thought that these allow the dissolved nitrogen to rapidly return from the blood into the lungs without bubbling.

On the surface, dolphins can empty and fill their lungs in a fifth of a second, exchang­ing 80-90 per cent of the lungs’ stale air with a fresh intake. Humans exchange only 30 per cent with each breath.

Speed and agility aside, it is the dolphin’s finely tuned acoustic sys­tem that stands out as its most re­markable adaptation to the marine environment—a world where sound travels almost five times faster than in air.

The sensory equivalent of our eye­sight, a dolphin’s echolocation sys­tem is based on the sending and re­ceiving of ultrasonic clicks which some­times reach frequencies of 220kHz. The sounds are thought to be gener­ated in the nasal passages behind an organ called the melon, a waxy oval-shaped mass in the dolphin’s forehead that focuses the clicks into a narrow beam and projects them forward.

The returning soundwaves are picked up and passed along oil-filled sinuses in the lower jaw, eventually reaching the inner ear, from which a three-dimensional acoustic picture of the contours and density of the sur­roundings is formed.

The time lapse between the outgo­ing click and the incoming echo gives the dolphin an idea of distance from an object, while variation in the strength of the signal on the two sides of its head enables it to assess direc­tion.

Dolphins produce two types of sound: pulsed clicks used for echolo­cation (these can be produced at a rate of more than 100 clicks per sec­ond), and unpulsed whistles, squeaks, buzzes and yelps, which carry further, and are used in group situations during feeding, courting,playing, excitement, distress, and as a personal acoustic signature.

Dolphin sonar is a highly sophisti­cated sense, able to track multiple ob­jects simultaneously, and “see” in three dimensions. Echolocation ex­periments have shown that dolphins can distinguish between solid and hollow spheres. So, like hospital technicians using an ultrasound scanner, Kaikoura’s duskies can prob­ably tell whether a nearby human swimmer is pregnant, and, from ex­amining her muscle tension, may even know whether she is relaxed, frightened or exhilarated to be in the dolphins’ domain.

With all these impressive abilities, it is little wonder that dolphins have been revered from classical Greece to the contemporary Pacific, where some cultures believe that they em­body transmigrating human spirits. Maori have a special regard for dol­phins (tepuhi or aihe), often linking them with taniwha—spiritual beings which inhabit the seas and water­ways of Aotearoa.

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Sun rise splashes the sky orange over Akaroa Harbour, and our eyes are peeled for tell-tale fins breaking the mirror water. A little over a metre long, and ghostly grey, a group of six Hector’s dolphins come barrelling up to the boat from astern, their clear white underbellies shin­ing through the murk like gleaming teeth. They draw level, peer up at us like playful children out for a game of tag, then dart past with vigorous bursts of their powerful flukes.

One juvenile dolphin swims next to us upside down, tail-slapping the surface, while further ahead a small group surf in on a swell. For the next half hour we are in the middle of a dolphin party. Hectors of all sizes surround us; a main group cruises alongside in a whooshing, panting chorus, while from time to time mav­ericks from outside dart into the herd and peel off with followers at high speed.

Many are characterised by nicks and tooth rakes on their flanks and fins—the result of playful jousts. Such mock aggression also includes “pouncing,” where one dolphin will literally jump on another as it sur­faces. Real tooth-baring aggression is momentary and rare, and the recipient does not retaliate, but flees rapidly. Hector’s dolphins seem to live by the maxim “Retreat is the best line of defence”—perhaps a wise move for a small dolphin whose main predators are sharks.

Hector’s dolphins are found only in New Zealand, and are the world’s smallest (maximum size 1.5m) and probably rarest oceanic dolphins. Out on the water their most recognis­able trait is a rounded dorsal fin—all other New Zealand dolphins have crescent-shaped dorsals.

Named after Sir James Hector, a nineteenth century curator of the Co­lonial Museum in Wellington, the spe­cies is most regularly seen around South Island coasts. A few are seen off the North Island’s west coast, with only very occasional stragglers elsewhere.

Otago University biologists Drs Stephen Dawson and Elisabeth Slooten have become synonymous with Hector’s dolphins research since they began their pioneering popula­tion studies on the species in 1984. Their anatomical research, exhaus­tive acoustic work and projects on behaviour, population and the im­pacts of pollution and set-netting have all received international recog­nition from bodies such as the Inter­national Whaling Commission.

Much of this work has been done on a shoestring budget. In 1984 Slooten and Dawson converted their old VW Kombi into a mobile home and travelling lab for $100. Trailing a rubber dinghy behind, and depend­ing on sporadic cheques and food parcels from their parents, they set out on an 8400km dolphin-counting odyssey.

The result was a population esti­mate of 3-4000 Hectors for the whole country. For the stretch of coastline between Motunau and Timaru, they estimated 740 animals. But by 1988, some 230 of those dolphins—more than a quarter of the resident popula­tion—were estimated to have drowned in set-nets, sparking fears that Hector’s dolphin could be on the road to extinction.

Given the animals’ sophisticated sonar apparatus, the two biologists were at first puzzled as to why the dolphins could not detect the nets and avoid them.

After further investigation they concluded that Hector’s dolphins pe­riodically switch off their echoloca­tion systems in familiar waters. Even with the system on, in the heat of chasing prey they may fail to detect the monofilament nylon set-nets used by local fishermen. Besides, if they do detect a net, it may not be interpreted as a lethal obstacle. Once entangled, however, the dolphins cannot reverse out, and drown within a few minutes.

Having established the cause of the prob­lem, Slooten and Dawson turned their at­tention to the dolphins’ reproductive rate, and found that it was little higher than their natu­ral mortality— the extra losses due to set-net en­tanglement were not be­ing offset by increased reproduction. The re­searchers estimated that maximum population growth rate in the ab­sence of human impacts was a modest 2-4 per cent. At that rate, the Banks Peninsula population could increase no more than 15-30 a year, whereas the average number killed in set-nets between 1984 and 1988 was 57 per year.

The implications were obvious, and in 1988 the Minister of Conserva­tion took the precautionary step of de­claring a 1170-square kilometre area of sea off Banks Peninsula a Marine Mammal Sanctuary. Commercial gill-netting is now banned year-round, amateur gill-netting banned during summer, and stringent restrictions are placed on how and where nets may be set.

Dolphin deaths are a problem not just in New Zealand waters. Over the past three decades as many as 12 million dolphins may have been killed in the eastern tropical Pacific tuna fishery as by-catch. Deliberate kills and pollution-related die-offs account for additional tens of thou­sands of dolphin deaths each year, and no one knows how many thou­sands of dolphins have met their end entangled in the giant “wall of death” driftnets of the Pacific.

With few accurate records of past population size, it is difficult to as­sess the true state of global dolphin populations. However, the main spe­cies to be found around New Zealand (Hector’s, dusky, common, bottlenose and orca) are listed among the spe­cies “significantly reduced in at least part of their range” by the Conven­tion on International Trade in Endan­gered Species (CITES).

New Zealand dolphins have one of the world’s highest rates of DDT con­tamination from agricultural run-off into rivers and coastal areas, and this poses an ongoing risk to their repro­ductive health. There are also tuna and other fishing-related deaths in nets off New Zealand caused by foreign-registered     “super-seiners” which fish from Great Barrier to North Cape during the summer months.

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On the drive back to Christchurch in Liz Slooten’s juddery old flatbed ute, the conversation shifts from set-nets to the finer points of dolphin communi­cation. Above the racket of the diesel engine Liz explains how she and her partner have tried to link Hector’s dolphins’ high-frequency clicks to observable behaviour patterns.

After analysing 7662 Hectors’ “sound bites,” they found that the use of complex click patterns in­creases as the dolphin group in­creases in size, suggesting a role in social interaction. A particular type of ultrasonic click was found to be associated with feeding, and “cries,” the only sound in their repertoire audible to humans, were usually made when dolphins were jumping, tail-slapping and chasing each other in active play.

Slooten and Dawson’s work with Hector’s dolphins is about as far as anyone has got with unravelling how dolphins communicate in the wild. Even so, they are wary of making grandiose claims about dolphin lan­guage.

Liz feels that our human fixation with verbal communication also needs to be reconsidered. “Animals can ‘read’ body postures and sense human intentions like aggression,” she says. “They are not dumb beasts. Dolphins may not use sound as a language in the sense that we know it, with syntax or grammar, but that does not mean they cannot commu­nicate complex information.”

US dolphin researcher Greg Stone, who has been in Akaroa as part of a three-year research programme to as­sess the effect of the sanctuary on the Hector’s dolphin population, agrees. “It’s a tantalising notion that dol­phins possess a culture or a con­sciousness, but I don’t think that is the case. They are animals with a world of their own, somewhere in there with chimps, dogs and cats. Sure, they can recognise boats, and possibly individual people, but I don’t see any telepathy-type stuff.”

Much of the overseas work on dol­phin language has been conducted with bottlenose dolphins—the large “Flipper”-type dolphin with its per­manently smiling mouth and friendly manner. In comparison with Hectors, research into bottlenoses is in its in­fancy in New Zealand. The first base­line study of a specific population is being brought to completion at the moment by one of Slooten and Dawson’s students, Jami Williams. Over the past three years she has carried out surveys of bottlenose dol­phins in Fiordland’s Doubtful Sound. By photographing nicks and scars, Williams has identified 39 individu­als which appear to reside in the Sound year-round. Allowing for those individuals without distinctive marks, the resident population prob­ably numbers fewer than 70.

Large though they are, bottlenoses are not the biggest dolphin species. That honour goes to Orcinus orca, better known as the killer whale. Male orca can reach nine metres in length, and weigh up to eight tonnes. They have the widest distribution of any marine mammal, ranging from the tropics to the Arctic and Antarc­tic.

Jet black from the tip of the snout to the tail, with a white patch behind the eye, distinct black-and-white markings underneath and an unusu­ally large triangular dorsal fin, the orca (meaning “devil” in Latin) is in a class of its own.

In New Zealand, the species is most commonly encountered in Cook Strait or in larger harbours such as Wellington and the Bay of Islands. At Kaikoura orca are treated like royalty, with their arrival announced on the radio.

Just a few weeks before my trip there, Brent McFadden had reported a pod of several orca passing through Kaikoura’s South Bay. What he calls a “scout group” of duskies immedi­ately went to meet them in the open water, while the calves and main dusky herd moved close inshore for protection.

McFadden’s interpretation is that the duskies went out to size up the orca, having heard them coming. Per­haps, he conjectures, they may even have been prepared to sacrifice them­selves to stave off an attack on the main group. “The duskies came up fast and, without hesitating or slow­ing down, wove in and out of the orca pod. The orca didn’t attempt to catch the duskies—it seemed to be a game in which they sounded each other out,” he recalls.

“The scouts returned to the main pod, and they all moved into the shallows around the rocks—closer in than I have ever seen them before.”

The orca’s fearsome reputation as a predator is legendary, probably stemming from 18th century Euro­pean whalers who witnessed “killer whales” tearing the lips and tongues from great whales several times their size. The writer A. J. Villiers de­scribed just such an attack, on a blue whale, in 1925: “Two of the pugna­cious killers attached themselves, one on either side, to the great mam­mal’s lower jaw, and appeared to be bearing down upon it with all the strength of their furiously struggling bodies, while two other of the assail­ants kept making short furious rushes at the great whale, and seemed to hurl themselves up and down on his exposed back, their writhing little bodies sounding on his body with great thwacks.”

The whale was killed, and the orca indeed fed on its tongue. “They had attacked the giant for nothing more than the delicacy of his tongue,” con­cluded the writer.

The orca’s eccentric taste for whale tongue formed the basis for a remark­able co-operative whaling venture between humans and orca in Two­fold Bay, Australia, a century ago. In his book Killers of Eden Tom Mead describes how a pod of orca would herd humpback whales into the bay while a local whaling family rowed out to harpoon them. “The tongue was the only part the killers would eat, and it was their reward for the help they gave.” This curious behav­iour took place from 1860 until 1930, when “Old Tom,” a large male orca, was found washed ashore dead. He had been helping the whalers for over 60 years.

Besides whales, orca are known to hunt dolphins, sharks and various types of seal. Off the coast of Patagonia orca lunge out of the surf on to a steep beach to pursue seals even on to land, manoeuvring around on their flippers before shuffling back into the water and out to sea to devyour their victim. Although poten­tially dangerous to humans, there are no authenticated accounts of any fa­tal attacks.

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Of all dolphin  behaviours, the most baffling—and tragic—are the strandings. New Zea­land has one of the highest rates of strandings in the world, with four localities being particularly infamous traps: the Chatham Islands, Mahia Peninsula, Farewell Spit and Muriwai. Since stranding records began in 1978, there have been 146 common dolphin strandings, 142 bottlenose, 73 dusky, 59 Hector’s, 49 orca and a massive 5442 pilot whales. In all species except pilot whales, strandings have been individuals or small groups of no more than ten. For some reason, pilot whales strand en masse.

Various theories for stranding have been advanced. Autopsies on some dolphins have shown parasitic ill­nesses that infect and block air pas­sages, and thus impair the animal’s acoustics. Other animals may simply become distraught after net entangle­ment or damage from boat propellers. It may be that ocean-going species are not used to close, inshore waters, and become disoriented by sloping sand­banks and deceptive topographic fea­tures. Some scientists believe the phases of the moon play a part, others that magnetic field anomalies are to blame, but as yet there is no clear answer, and the strandings continue.

While strandings can and do bring about great displays of public sympa­thy and concern, it is the notion of cetacean intelligence that produces the greatest human fascination. We observe their incredible ability to imitate and learn, consider their his­tory of co-operation with humans, and wonder if there is some empathy deeper than instinct behind those gentle eyes.

Since experiments began in the 1950s, a variety of empirical meas­urements of dolphin intelligence have been put forward, such as the ratio of brain volume to body surface area (which for the bottlenose dol­phin reaches 5.6, compared to the human value of around 7.4, and 2.5 for the chimpanzee), and the ratio of brain weight to spinal cord (which in humans is 50:1, in dolphins around 40:1 and in apes 8:1).

But these measurements offer lit­tle more than one-dimensional com­parisons. The key area of the human brain linked to intelligence is the neo­cortex. In dolphins this part covers 98 per cent of the cortex—a higher figure than for humans. Does this imply cognitive ability? A conscious­ness in the oceans? Indeed, are dol­phins our brothers and sisters under the skin?

Research with captive dolphins has revealed that they are good mim­ics who can copy a human voice or computer-generated sound, respond to voice commands and even repeat words spontaneously. In the US, bottlenose dolphins have been trained to perform tasks using a whis­tle language similar to that used to control sheep dogs. Others have un­derstood and responded to “sen­tences” of 2-5 words, as well as mixed sound and gesture commands.

The dolphin’s apparent intelli­gence, aquadynamic design and so­nar capabilities are also the kind of faculties military forces wish to pro­cure. Recognising the dolphin’s ten million year competitive advantage over Homo sapiens in the sea, the US Navy drafted its first recruit 30 years ago, and has since trained more than 200 dolphins to perform such tasks as attaching explosives to ships, de­tecting mines and guarding military bases. A team of dolphins was one of the less publicised forces sent to Vietnam in 1971. Their job was to attach mines to Vietnamese targets, detach themselves and swim away.

“Dolphin is a powerful word,” says author, linguist and would-be inter-species communicator Wade Doak, doyen of New Zealand’s dolphinologists. With his wife Jan, Doak has spent much of the past 20 years exploring dolphin intelligence and communication.

Early years were spent developing an unorthodox diver’s “dolphin suit,” with fused flippers and hank_. operated “fins,” and using hydrdv, phones to record and play back dol­phin sounds. He recalls those days “before the Wright brothers learned to fly,” when dolphin encounters were a “hello-goodbye” affair.

“Now there is a global desire to swim with dolphins,” he remarks. “In the early days we were scared of dolphins. But as more dolphins were captured, people became less scared of them, and started to think of them as having some relationship with humans.” Despite the shift in public perception, he still thinks many peo­ple have a distorted view of dolphins While some deify and “Disneyfy” them, others regard them with “insti­tutionalised skepticism.”

Doak is scathing about the more outlandish “New Agers” he has en­countered, recalling with disdain a group of “underwater dolphin blithers” who, in the early 1980s, “stood around naked, calling and clicking stones in the surf. After that incident I got so many crank calls that I had to go ex-directory.” He knows of people in the US who be­lieve strandings and driftnet deaths are deliberate suicidal messages from dolphins warning us of imminent en­vironmental collapse.

Perhaps because communication and intelligence are hard to quantify or prove, Doak refuses to be pinned down, preferring to call dolphins our “closest brain neighbours.”

“I think it is an intuitive thing, not like clinical psychology where you apply some kind of IQ test. You can’t just put them in a lab and say, ‘There, that’s how intelligent they are.^—

He is also uneasy about being asked to describe his most profound dolphin encounter (he calls them “in­terlocks”). “Perhaps it was when we set up a two-way underwater tel­ephone communication system in the water at Whitianga with a dolphin we called Rampal. He responded to our excitement with clicks and noises, even though we were not al­ways in the water with him. That was probably the most abstract level ex­perience. But then there was the dol­phin that pointed out a hook in an­other dolphin’s skin to a diver, asking for help, and another dolphin that led a diver to his lost camera.”

Doak thinks that captive dolphins involved in behavioural experiments do not take their fish rewards just out of appetite, but also out of boredom, and a need for stimulation. After all, he points out, there is not much else for a dolphin in an empty tank to do all day. He recalls experiments in which the subject dolphin began to give the wrong answers, and brought the fish to the scientists!

In another experiment that re­warded new behaviour with a fish, the dolphins came up with so many new moves that the team were un­able to keep up with them. Could these animals have been making fun of our naive research?

Doak gives a wry smile: “I prefer to let people form their own impres­sions from intuitive feelings. Intelli­gence is not the kind of thing you can calculate or draw a chalk line around—there are shades of grey around the edges.”

As for me, I’m keeping an open mind. By the time we have it all worked out, the dolphins will have long since said, “Goodbye, and thanks for all the fish.”