High Life magazine sent me to Sweden to listen for howling wolves in the night. This was one of my favourite-ever assignments – short, but thrillingly memorable. The original story page is here.

A breeze moves the leaves of aspens in the night gloom. One branch holds another, creaking. Marcus Eldh, our guide in the vast forests of central Sweden, speaks like the air, in a whisper. “They are here. All around us. I will try.”

We none of us move a muscle. Stock-still in the pitch dark, the gravel track crunching faintly beneath our shifting heels, we draw closer together in our minds and tilt our faces to the pine-tops, jagged against a purple sky.

Marcus’s torchlight flashes a brief signal. Then he calls to the wolves, a lingering, mournful howl, urgent and quizzical, fading on a distinctive rising note that shivers the stony night. Cold silence resumes. We wonder what might follow.

TV wildlife teams may camp out for weeks in one location to encounter animals in the wild. We have 36 hours – a couple of nights in a rural guesthouse, a couple of evenings out walking in the woods. I’m not expecting to see a wolf, but I’m hoping to feel their presence.

Canis lupus, the grey wolf, once lived all across the northern hemisphere, from America and Europe to Russia and Central Asia. Globally, the species is still thriving. But taken regionally, wolf habitats have shrunk dramatically and many populations are under threat.

The situation in Scandinavia is dire. From the 19th century, when Sweden hosted around 3,000 wolves, today 210 survive. Norway has twenty, just over the Swedish border; Denmark perhaps one or two. In the teeth of fear, ignorance and entrenched hunting interests, the wolf here is just barely clinging on.

Humans have hunted wolves for perhaps 15,000 years, probably since the first farmer found the bloodied carcass of the first semi-domesticated sheep. Yet like the American bison, wolves in Europe thrived until human society began to encroach on their habitats – and until technology began to facilitate quicker, easier kills.

When that happened, in the 19th century, it was as if all the pent-up fear – generation after generation of huddled humans listening to predatory lupine howls in the night – exploded. Wolf populations were decimated. By the mid-20th century, wolves had been hunted to extinction in Sweden: only when the last individual was shot in 1966 did the Swedish government place the wolf under legal protection – too late.

For years, nobody saw or heard from them. Then two were spotted during the winter of 1981. In 1983, a man out to collect his post saw a moose pursued by eight wolves on a country road. Geneticists working at Skandulv, the Scandinavian Wolf Project – a cross-border conservation body, headquartered at Grimsö in central Sweden – have since determined that the country’s entire population of wolves is descended from just five individuals who returned in the 1980s.

With such a narrow genetic base, inbreeding is embedding congenital abnormalities, notably skeletal distortion. Ideally, Sweden’s wolves would mix their genes with the larger Finnish-Russian population to the north. But Swedish law forbids the presence of wolves in the whole northern half of this vast country, to protect the reindeer breeding grounds.

Worse, in 2010 Sweden’s government lifted the ban on wolf-hunting, granting licences for a set number of wolf kills each year. The decision was made ostensibly to reduce inbreeding levels, but critics say targeting of inbred animals was inadequate, and suspicions persist that it was more of a sop to Sweden’s powerful hunting establishment than anything else. The European Union formally reprimanded Sweden over the policy in 2011. The Swedish government may legitimately be seeking to limit the number of wolves allowed to roam wild, but their methods have divided opinion. If lawyers conclude the hunt contravenes EU law, Sweden may yet end up in the European Court of Justice over it.

Per Ahlqvist, Skandulv’s Swedish field coordinator, refuses to be downhearted. “I grew up in a time when there were no wolves at all,” he says. “So I am comfortable with the current situation.”

In a wood-beamed upper room at Grimsö’s Wildlife Research Station – not the gleaming science lab of my imagination, but a rustic clump of barns – Ahlqvist is giving a group of wolf-watching visitors a crash course.

“Wolves are capable of anything,” he says. “I’ve seen 19th-century church records from Finland that say wolves killed 70 children over two winters. A lynx in a sheep pen would kill one or two sheep, but a wolf would kill them all. I once saw 32 adult sheep torn apart in a field. Killing is fun for the wolf.”

But does that mean they deserve to be exterminated?

“We have a very contradictory attitude to wolves,” says Ahlqvist. “They’re welcome, but not tolerated.”

Moreover, he says that without a clear policy from government, both hunters and conservationists are becoming increasingly unwilling to explore compromise.

“Yet conservation can include hunting,” he says. “But what is Sweden aiming for? A thousand wolves? A hundred? None? It was not politically correct twenty years ago to say we don’t want any wolves, but today many people say it.”

If some see the wolf as a threat, demanding complete eradication, others envisage a future for wolves within the rural economy. Near Grimsö, where rolling forests of pine, birch and aspen close in around the small railway town of Skinnskatteberg, tourism initiatives are challenging the traditional industries of mining and timber, blending a hunter’s wilderness mindset with a conservationist’s environmental perspective.

Horrified in 2002 to overhear tourism officials advising visitors to go to Stockholm Zoo if they wanted to see moose, local graduate Marcus Eldh set up his own company to entice tourists into the woods. Eleven years on, he is one of Scandinavia’s leading nature guides, working with conservation authorities to run closely controlled wolf-watching tours, alongside trips to spot bear, lynx, beaver, rare birds and, of course, the ubiquitous moose.

“My goal is that the forest be worth more for tourism than for timber,” he says.

Local people are feeling the change. Sheep-farmer Allan Nykvist says that he is now benefiting from the wolves: since opening a farmhouse B&B, half his turnover comes from wildlife-happy tourists booked on Marcus’s trips.

And that’s why I’m here, seated on larch logs by a Skinnskatteberg lake, getting acquainted over mid-afternoon soup and cinnamon buns with a small group of, intriguingly, mostly Swedish tourists, some of whom have travelled all day for the chance of a wolf encounter. Shadows climb the pine trunks as we depart. At a junction of dirt roads, loomed over by trees, bodies tumble out of Marcus’s minibus, adjusting headgear and zipping on layers.

“We must be silent. Don’t walk like this,” whispers Marcus, sliding a boot noisily over the gravel track. “Do this.” He treads heel-first on the grassy verge.

The walk is spectrally quiet. Hemmed in by the forest, which I sense rolling unbroken from the Atlantic coast in a great wave eastwards to the infinity of Siberia, we are puny. Mid-forest, clouds roil in a zombie lake as Marcus’s finger picks out a raven, cawing and circling above the far shore.

It’s found meat, he mouths. The raven will lead us to the wolves.

Puffing up a scrubby hill, ringed by expectant trees, we halt at Marcus’s palms. There. In mud. A paw-print.

“It’s fresh,” he says. “And it’s small. Maybe a female. Or perhaps a pup.”

I can’t take my eyes off it. They are here. Among us. We are in their forest. Uninvited.

Down the hill, the trees close in. Dusk is settling. The silence swaddles. Branches creak. A brook trickles.

Then, faintly, I hear a plane whooshing far overhead, and it’s like the spreading warmth of home. One familiar sound makes the forest sensible. We regain the road in pitch-black night, and I want to live here forever.

Before we build a fire Marcus tries calling to the pack. And out of the chill and the dark comes an answer, a high echo of howls circling the horizon. Yes, they are here.

Shining-eyed, we grin. But the expected prickles at the back of my neck have not materialised.

Marcus, too, isn’t frightened.

“The last person killed by a wild wolf in Sweden was in 1853,” he says. “Two people are killed each day on the roads. If I was scared for my life I would stop driving.”

After fireside wraps of wild boar and an entirely appropriate vargtass (“wolf’s paw”) – lingonberry juice with a dash of vodka – I spot a hunter on the horizon, three stars twinkling in his belt.

Marcus nods, then shows me how the familiar stars of Cassiopeia melt into Sarva, the moose, a constellation of the indigenous Sami people. Out here, Orion’s belt is three hunting dogs.

Near midnight, Marcus leads us away from the huggable fire. For half an hour we walk into nothingness, our torchlight useless against velvet. On a wooded slope, sitting blind amongst the pillars of a natural cathedral, time stretches invisibly.

Marcus’s torch flashes, telling us he’s about to howl. After the echo, we wait. There is only silence and darkness. Then a dry twig cracks, fifty metres distant in some other world.

They are here. Of course they are. Oddly, that feels good.

Back beside the huggable fire, somewhere near 2am, Marcus calls again. This time the response is instant. Howls ring through the forest, as adults and pups call back and forth, communicating their location to each other. Their scout paces nearby, thirty metres from our fire, his paws snapping more twigs in the dark as he, too, howls his presence.

When it’s over we huddle, talking of the sound as comforting, even calming. We saw no wolves, except in our heads. Yet their voices opened old, old doors in the mind.

Unspoken in the moment, all of us are glad for the fire. And for each other.

You can see wolves in any zoo. But to hear wild wolves howl, you must go and find them. After midnight. In the deep, dark forest.

Best not go alone.