The Sultans of Streams

Not long ago Britain’s otters were all but wiped out by chemicals leaching into rivers. They’ve made a comeback.

This story appears in the February 2013 issue of National Geographic magazine.

I am hunting otters with Charlie, the two of us in wet suits, our bodies submerged, level with the sea. The tankers are sliding in toward the piers and gas flares of the oil terminal at Sullom Voe. This is Shetland, at the far northern tip of the British Isles. Helicopters from the North Sea rigs clatter into the airport behind us, but they seem a world away.

Charlie Hamilton James has been photographing British otters ever since he fell in love with them during their decline some decades ago, and has followed them obsessively as they have made their way back to health. He knows how to stalk an otter and has told me the technique: Your face as low in the water as it can go, neoprene helmet well down, and quiet—no whispering (gestures better), your breath quiet, your fins quiet, and if you’re lucky, you might get near one.

Tiny flatfish move away from our feet in the shallows. Two seals come to inspect us, goggle-eyes, fat submarine bodies. But the otter we thought was here, which an hour ago was a distant three-part silhouette in the binoculars, a disc of a head, the arched back, a long strong tail, or as it is beautifully called, the rudder, is nowhere to be seen. Male otters display like this, with the rudder prominent, in a kind of swaggering signal to other otters that this is their territory. We look and wait while the cold seeps into the bones.

Then Charlie taps me and points at some weedy rocks just inshore. A mass of damp bladder wrack and serrated wrack, a tangle of ochre and khaki. An anonymous coastline. Nothing there. Then I see him. A mound of soft flesh just above the tide. The drying chocolate-colored pelt, which for so many centuries was hunted for its warmth and thickness, has been combed into peaks by the otter’s own movement through the water. He is asleep, more than a yard long, perhaps 15 or 20 pounds in weight, the luscious and glossily furred animal lying back in his nook away from the wind. His belly and pale chin are upward, his rucked pelt thick up around him in folds, the toes of his front paws open, the webs visible between them, his four legs in the air. Is he snoring? I can’t quite tell. His long whiskers, which are there to detect movement in the water, pressure sensors responding to the pulse from a quivering fish tail ahead, extend out from his muzzle, as wide on each side as the width of his head. His head is an antennae cluster, his whole body a seek-search-and-destroy organism. Not now though. Here is a sultan on his divan. The laid-back body oozes dominance, the perfect at-homeness of a top predator, the rollover luxuriance of animal ease.

There is only one species of otter in the British Isles, Lutra lutra, the Eurasian otter, which is just as much at home in the sea as in fresh water. The only difference is that sea-living otters must wash in freshwater pools frequently to keep their coats free of salt and insulatingly warm. It is a creature that has been familiar to human beings for many millennia. It was probably one of the most widespread mammals in the Old World. The word “otter” was part of the language spoken by early Europeans thousands of years ago. Otters were a constant presence in the river valleys where people settled, and were often trapped, pursued by hounds, and disliked by fishermen. The otter’s face, or “mask,” was favored for the most elegant of sporrans, those furry purses kilted Scotsmen like to wear around their waists. “All men that keep Otter dogs ought to have a Pension from the Commonwealth,” the great Izaak Walton wrote in The Compleat Angler in 1653. But the otter hunters never destroyed the otters, and the otters did not eat all the fish. A form of man-otter-fish balance persisted through the centuries.

Estimates of historical numbers are difficult if not impossible. The otters’ ability to disappear, to melt into the water, to slip into the background as if they had never been there meant that they became the all-present but hidden secret of the landscape. Elusiveness was their calling card.

The first signs of disaster, in the 1950s, were scarcely understood for what they were. At the same moment, the peregrine falcons began a precipitous decline. Problems developed in the 1940s with use of insecticides, fungicides, organochlorides, and the all-purpose wildlife killer DDT. These chemicals were used in industry to treat wool and cloth, get rid of insects and fungi, preserve seeds, and to dip scabby sheep. From the 1950s to 1970s organochlorines and PCBs, used as coolants in electrical transformers and stabilizers in paint and many other products, led to widespread pollution of waterways. Such persistent substances do not break down and disappear when they are out in the environment. They accumulate as they move up the food chain: a tiny amount absorbed by a microbe, more by a microscopic shrimp, still more in a small fish or eel, yet more in the grand predatory fish, and most of all in the top-predator body of the otter. What should have been a system for delivering goodness had turned into an escalator for poison.

More than a decade of ignorance and inaction went by. Only in the mid-1960s were organochlorides banned in England as a sheep dip, largely because they had been identified as the reason that the populations of peregrine falcons and many other birds and mammals were declining. They remained legal as a seed dressing until 1975 (and for some specialist uses until 1992). And even when banned, they were replaced by organophosphates and synthetic pyrethroids that were also highly damaging to ecosystems. Only in 2006 was a final ban placed on the substances, which had been diminishing the life of English rivers for more than half a century.

The otter population collapsed, perhaps through lack of fish, perhaps through individual otters being poisoned. A national survey in the late 1970s found that only 6 percent of 2,940 English riverside sites had any evidence of them. Across large swaths of England, there were no otters at all. The rivers had died, and the otters had died with them. Only in the far west and on the Welsh borders had the animals survived. Otters went extinct in the Netherlands, Belgium, and Luxembourg. Most of France, Germany, and Italy were otterless. They were rare in the bulk of Norway and Sweden. Numbers stayed high in Scotland and eastern Europe, but elsewhere it seemed possible that the otter would disappear entirely.

Agonizingly slowly, as the chemical bans took effect, the population started to climb back toward health. By 1984-86, the proportion of English riverbanks occupied by otters had risen to 10 percent, and to 59 percent by 2009-10. Gradually otters pushed back eastward across the country, so that now only the London area and some northern industrial cities remain otter-free.

But the revival remains fragile. A small population in Kent has disappeared, perhaps because of road traffic killings. Deaths from cars are thought in some counties to be keeping pace with annual cub production. Low-level diffuse pollution characterizes nearly every stream, and far too much water is extracted for them to be in good shape. The pelts of otters killed by cars have been found to contain traces of the anti-inflammatories ibuprofen and diclofenac. In some areas where otters have returned in numbers, there is a steep increase in the wounds inflicted otter on otter, probably as a result of competition for territory.

Fragile, but not all bleak. Charlie and I went to a river in Dorset in the south of England. In the middle of a small market town, in the middle of the day, with the people crossing the footbridges over the river between the supermarket and the town park, taking their dogs for a walk or the children for a romp, we watched for four hours a family of otters, a mother and two nearly full-grown cubs, fishing and playing on the river. People stopped and chatted about “their” otters, amazed that we were amazed to see them there. They have been a regular sight in the town for the past couple of years.

But look closely and you can’t help but be amazed at the high-performance intensity of those sleek liquid bodies nuzzling and shoving at the bankside vegetation and coming up spattered with the green speckles of duckweed, all three members of the family often sliding close up against each other, intensely sociable, fishing and hunting in the riverbed for bullheads and even minnows. It is a fierce and busy, high-turnover life: The repeated dive down often coming up with prey in their teeth, and then tossing it to the molars at the back, when one after another the otters chomp away with the upturned head and delighted air of a man in a restaurant who has just won the lottery and is now chewing in triumph on the juiciest of steaks.