BBC Wildlife Magazine
Mysteries of the deep
Uncovering the secrets of beaked whales
Like seeing an ichthyosaur caught on camera. That's what it felt like watching recent footage of a True’s beaked whale filmed off the south coast of Pico Island in the Azores. It was the first time this cetacean has been filmed underwater. More than that, this vital new evidence is leading scientists to believe that it may be a discrete Northern Hemisphere species. If so, it will be the fifth new species of beaked whale discovered in the past 25 years.
Natacha Aguiler de Soto, a marine biologist at the University of St Andrews who identified the True’s beaked whale in the film and has been studying beaked whales for 15 years, was amazed when she made her discovery. “Imagine! These are animals the size of elephants that we just can’t find. They’re a mystery.” Aguiler De Soto went on to acknowledge: “We don’t know how large the populations of True’s beaked whale or any other beaked whale species are. So the populations could decline and we would never know.”
Beaked whales are truly strange creatures. They are the deepest-diving of all marine mammals – a Cuvier’s beaked whale set the record in 2014, at 2,992m – and spend over 90 per cent of their lives in the dark depths of the pelagic ocean. One good reason why they’re so difficult to see, let alone study. Yet they constitute our second largest cetacean family, Ziphiidae, after oceanic dolphins.
The six genera and 23 species of beaked whale that have been seen and described so far range from the relatively common Cuvier’s, Sowerby’s and bottlenose whales, to more obscure species such as Hector’s, Shepherd’s, Stejneger’s and Longman’s. They range in size from the huge northern bottlenose whale of the North Atlantic, which can reach 9.8m in length, to the pygmy beaked whale of the South Pacific at up to 3.7m.
As a family, beaked whales might be said to be very successful, being present in every ocean. Yet it’s only with the advent of digital video and photography that we have been able to identify these enigmatic creatures in their own environment. Look up True’s beaked whale and in even the best reference works you will find blurred images of ‘probable’ sightings. One respected cetacean field guide notes of True’s distribution: “Movements, if any, unknown. Population: perhaps naturally rare.”
Such ‘data deficiency’ is enough to lure any ‘whalehead’ on. But whose imagination wouldn’t be sparked by the notion of such rarely seen large animals inhabiting the oceans? They certainly present extreme identification difficulties – especially because the key diagnostic is the shape of their prominent pairs of teeth, or tusks, which jut out of their lower jaws. In some species, these protuberances can completely grow over the beak, like a muzzle. It’s only because beaked whales suck in their main prey – squid – that they thrive with such an apparent handicap.
In Wellington, New Zealand – a beaked whale hotspot – I was lucky enough to meet Anton van Helden, then curator of cetaceans at the Te Papa Museum, who might be said to be the world expert on beaked whale skeletons. Van Helden took me into the
bowels of the museum. Astonishingly, arrayed in row after row on metal shelving, were the bones of the rarest cetaceans known. Nonchalantly, van Helden pulled out a box of beaked whale teeth – a collection the result, it seemed, of a very bad day in the cetacean dentist’s chair.
A RARE FIND
Even more amazing was the cranium of a spade-toothed beaked whale, so-called because its teeth resembled the sharpened spade used by whalers to flense (cut up) their catch. This scooped-out ski-slope of a skull, its lower jaw studded with stumpy tusks, represented, to date, one of only three specimens in the world. The species has still never been seen alive, although in 2010 a mother and calf beaked whale stranded in New Zealand’s Bay of Plenty were identified as this spade-tooths.
Of all beaked whales, the bottlenose are perhaps the easiest to identify, from their prominent melons – the bulbous foreheads that containn fatty oil now thought to function as a bio-acoustical aid. Other species in the family are also subtly marked. Arnoux’s, Blainville’s and Cuvier’s beaked whales bear patterns of scratches on their bodies, much like Risso’s dolphins – a result of tussles with squid and also maleto-male fighting.
A young Perrin’s beaked whale – “still largely unknown at sea” – may have a pale cape around its dorsal areaarea, a little like the white saddle on an orca. But this disappears as it matures and joins the other Ziphids in what seems to be a shape-shifting game of detection for us humans. We do not know their movements, their social or cultural arrangements, or where and when they breed. But then, we don’t even know the breeding grounds of the second-largest animal on Earth, the relatively common fin whale.
I’ve been lucky enough to have seen beaked whales off the Azores on a number of occasions. They are sublime creatures, suffused with a sense of their own mystery. At least, that’s how it seems to us. Last year, photographer Andrew Sutton and I watched a pod of Sowerby’s beaked whales off Pico’s black, basalt shores. These are very deep Atlantic waters, up to 5km deep.
The whales appeared out of the cool, calm sea just after dawn, the silver light making their presence doubly haunting. It was only as
their sharp, primeval beaks broke the surface that they revealed themselves. One female was followed by its calf. They moved quietly across our bows; the only sound they made was the soft plosive exhalation of their blows, readying themselves for descents into the depths.
Beaked whales can surpass even sperm whales, which may make dives 2km deep. Their spindle-shaped bodies are perfectly designed for the job; their pectoral fins fit into ‘pockets’ on their sides, almost like an aircraft’s undercarriage. It is their ability to forage in the benthic depths that places these shy cetaceans far from us.
I’ve seen thousands of whales in 17 years of watching and swimming with them, but this encounter in the Azores was special, made more so by the whales’ rarity – and d the threats they y face. A Cuvier’s be aked whale that stranded on n the Isle of Skye in 2014 had in ngested 4kg of plastic bags and other ru ubbish. When a Cuvier’s found beached in Norway in 2016 was discovered to have swa allowed 30 plastic bags, it was nicknamedd Plasthvalen, ‘Plastic Whale’, and became an emblem for public concern about plastic in the oceans.
Long seen as omens, whales retain their symbolic power, especially when they come into contact with us. The famous ‘Thames Whale’ may be the most filmed beaked whale ever. This northern bottlenose, a young female, met her sad end in February 2006, probably having taken a ‘wrong turning’ into the shallow North Sea and thence into the Thames, where she succumbed to stress and dehydration. Whales get their fresh water from the food they eat, and this animal was unable to feed on her usual diet of squid. She died on the riverbanks, despite a rescue effort estimated to have cost over £1 million.
Beaked whales act as a barometer of the effect we have on the ocean. Noise from human activity, unknown in the marine environment until relatively recently, has a severe effect on animals that rely on sound and their own natural sonar. Of 136 beaked whale mass strandings reported from 1874 to 2004, 126 occurred between 1950 and 2004, after the introduction of high-powered naval sonar. The evidence is mounting up. In 1998, 14 Cuvier’s whales stranded off Greece. This was extremely unusual: unlike other toothed whales, such as pilot whales, mass strandings are seldom seen in beaked whales, which live and dive in deep trenches far from shore. The incident occurred within a few hours of the onset of NATO mmanoeuvres, conducting triaals of a sonic array. In a 2008 episode that may also be linked to human activity, no fewwer than 18 Cuvier’s, four Soweerby’s and five unidentified beakked whales – and 29 pilot whalles – stranded in the UK and Irreland. Necropsies show that thhey all died around the same ttime. And in 2014, a series of seveen Cuvier’s whales stranded off Crrete in the Mediterranean durring US naval exercises. OOther studies of beaked whale strandings off Madeira that coincided with military sonar activity indicate that the whales may have been scared into surfacing too quickly, thus suffering narcosis, or the bends. Yet for all their rarity, beaked whales are no strangers to the waters around Great Britain. Oddly enough, one of the best places to see them has been from the deck of passenger ferries on routes from Portsmouth or Plymouth across the Bay of Biscay to Spain. I once saw a Cuvier’s beaked whale breach off the bow of one of these ships. It was a stunning sight.
FOR DEEP DIVING, BEAKED WHALES CAN SURPASS EVEN SPERM WHALES. THEIR SPINDLE-SHAPED BODIES ARE PERFECTLY DESIGNED FOR THE JOB.
The weirdly marked, bird-like head of this species has earned it the alternative name of ‘goose-beaked whale’, conjuring up medieval images of barnacle geese, supposedly born of barnacles. The whale owes its usual nomination to the great French naturalist, Georges Cuvier. When he discovered its skull in 1823, it looked so weird that he assumed it belonged to an animal that had long been extinct. It took 50 years for scientists to establish that it was still alive and swimming in the sea.
Intriguingly, recent research indicates that the eerie quality of these whales may owe something to our own past. In the culture of the Picts, who occupied northern Scotland between the third and the ninth centuries BCE, there is a persistent image of the so-called Pictish Beast, a curled embryonic shape often found in stone carvings (and possibly reproduced in their tattoos). Archaeologists have debated the meaning of this creature. Some think it is an invention of Pictish imagination, which often portrayed men with bird’s heads and other chimera. But others have seen the shape of a cetacean in its curves.
Certainly, bottlenose dolphins would have been familiar to the coastal-dwelling Picts. A community of bottlenoses still swim close to the shores of Spey Bay and the Moray Firth, and are subjects of a long-standing study by the charity Whale and Dolphin Conservation. Like us, our ancestors must have watched them too. Interred in a Pictish burial hoard discovered on St Ninian’s Isle in 1958, among the precious silver bowls and other objects, was the jawbone of a porpoise. Its presence seems to indicate a ritual importance for cetaceans among the Picts.
Historians Colin Macleod and Ben Wilson suggest that the Pictish Beast was inspired by a stranded Sowerby’s beaked whale. They base their theory on perceived similarities between the Beast’s eccentric snout and the Sowerby’s equally strange beak. Another historian, Craig Cessford, proposes that cetaceans had an even earlier significance for pre-Pictish people in Scotland, and that our fugitive relationship with these cryptic creatures extends yet further back into prehistory.
It is a powerful notion, to think of this rare animal emblazoned on a tribesman’s arm, its sinuous shape still remembered in stone a millennium later. And if the beaked whales seem like emblems of the ocean’s otherness, it is salutary to think that we barely know any more about them than our tattooed ancestors did, one thousand years ago.
IT IS A POWERFUL NOTION, TO THINK OF THIS RARE ANIMAL EMBLAZONED ON A TRIBESMAN’S ARM.