Wild Life

Kingdom of Foxes

In Iceland's Hornstrandir Nature Reserve, arctic foxes are thriving—and offering hope that the species will be able to adapt to a changing climate.

Amidst a multicolored carpet of wildflowers, a dark head appears. Wary, its nose twitching and eyes alert, an arctic fox (Vulpes lagopus) stands on its hind legs to get a better view as it scans the landscape for danger. Here in the Hornstrandir Nature Reserve on Iceland’s northwest coast, threats come not from hunters, as they do elsewhere in the region, but from other foxes seeking territories of their own.

Beginning in February, male arctic foxes spend a great deal of time and energy patrolling their territories and guarding them against the encroachment of interlopers. With each territory spanning nearly 20 square kilometers (7.7 square miles), it’s a lot of ground to cover, and the foxes can’t be everywhere at once. To make their presence more widely known to would-be challengers, the foxes bark; they howl; they make regular passes around their territories, marking the perimeter with urine—a chemical signal that says, “occupied.” When these auditory and olfactory warnings fail to deter intruders, males engage in physical combat to hold onto what’s theirs.

At stake in these territorial disputes is far more than a male’s place in the pecking order. In the arctic fox’s world, territories provide access to food resources, which in Hornstrandir means mostly nesting seabirds, but also eggs, insects, seaweed, crustaceans, and even carcasses of marine mammals that wash ashore. Controlling a sizable piece of real estate can mean the difference between reproductive success or failure, between survival and death.

Throughout most of the year, male and female arctic foxes live solitary lives. But each spring, they find mates on the tundra and devote the next several months to producing and caring for litters of up to 10 pups. The pairs remain monogamous throughout the breeding season, sharing the burden of finding food for so many hungry mouths. While the pups are nursing, males are the sole providers for their families, but once the pups are weaned—which happens within just two to four weeks—both parents join the hunt.

In less than a year, Arctic fox pups are sexually mature, which in most places prompts the young canids to set off in search of their own territories. But here within the safety of Hornstrandir, in what scientists call “The Kingdom of Arctic Foxes,” population density is high, and that means open territories are in short supply. As a result, adult foxes often ease their offspring through the transition, allowing them to stay on their birth territories through the following breeding season, which helps to ensure the young foxes’ survival.

If spring in the Arctic is a time of mild temperatures and plentiful food, winter offers a stark contrast. Situated at the edge of the Arctic Circle, between the North Atlantic and the Greenland Sea, Iceland and its permanent residents are at the mercy of the elements.   

Temperatures can plummet to -40 degrees Celsius (-40 degrees Fahrenheit) during the dark Arctic winter, and wind speeds have been clocked at 265 kilometers per hour (165 miles per hour). While many animals take their leave and migrate to avoid the winter chill, arctic foxes ride it out, relying on a host of physical and behavioral adaptations to see them through the inhospitable conditions.  

Not surprisingly, the species’ most striking and highly sought characteristic—its fur coat—is also one of its most important traits for enduring tough Icelandic winters. Like many creatures, arctic foxes replace their light summer coats with warmer winter ones when temperatures drop. But the seasonal transformation in this case is extreme. The depth of the arctic fox’s fur nearly triples between summer and late fall, resulting in a coat that insulates better than any other mammal’s. And the insulating fur doesn’t end there. Unlike other members of the dog family, arctic foxes also have fur on the pads of their feet, a trait that reduces heat loss as the animals travel across snow and ice.

In addition to a host of physical characteristics, arctic foxes also have a number of clever behavioral adaptations that enable them to survive Arctic winters. While cold may be the most obvious environmental factor to contend with, the winter months also bring a scarcity of food. In preparation for these lean, frigid daysthe foxes spend the summer months taking full advantage of the seasonal abundanceputting on a thick layer of fat as they go. To bolster their internal energy reserves, the predators also hunt more than they can eat, storing their kill in underground caches. Their drive to hunt doesn’t stop once a few meals have been safely stored awayScientists have found arctic fox dens filled with more than a hundred birds each, surely enough to get a few lucky individuals through even the harshest winter  

As the summer’s rich food resources begin to dwindle, the foxes settle in to a slower pace of life. Rather than continuing to hunt when prey is scarce and temperatures are coldest, they hunker down. While the foxes don’t hibernate, they wait out storms and cold snaps nestled in snow lairs or dens, protected from the howling wind and insulated by snow. There they remain curled up with their legs tucked under their bodies and their noses covered by fluffy tails, waiting for a break in the weather, and the possibility of another feeding opportunity.  

Partly because of these adaptations, arctic foxes are widely distributed across their namesake region of the planet, with established populations in Alaska, Canada, northern Europe, Greenland, and other islands in the far north. The cold-adapted foxes first reached Iceland some 10,000 years ago, during the last Ice Age, by crossing over vast expanses of sea ice. Then, sometime between 200 and 500 years ago, another dip in temperatures—which scientists often refer to as the Little Ice Age—allowed a second wave of arctic foxes to make their way to the island, an event that introduced important genetic diversity to Iceland’s fox population.

Today, Iceland is in many ways a haven for arctic foxes. The island nation is free of rabies, mange, and other fatal diseases. And unlike the more crowded predatory niche the foxes fill across most of the rest of their range, there are no other carnivores in Iceland with which to compete for prey. Outside the protective boundaries of Hornstrandir Nature Reserve, however, the country’s foxes do face a serious threat: hunting.

“Humans have battled the foxes since the settlement [of Iceland] during the 10th century,” says Ester Unnsteinsdottir, an ecologist at the Icelandic Institute of Natural History and co-founder of the Arctic Fox Centre. While they were once targeted primarily for their fur, Icelandic arctic foxes have also long been persecuted by farmers anxious to keep the predators away from their livestock. In 1295, the National Parliament of Iceland approved legislation that required any farmer with six or more sheep to either kill a set number of foxes each year or pay a fine. This legislation remained in place until 1792, when it was strengthened by ordering the slaughter not just of adults but of entire dens. By 1955, poisoning foxes had become a mandatory annual obligation for all property owners—a practice that remained in place until 1964, when it became clear that white-tailed eagles (Haliaeetus albicilla) were frequently unintended casualties of the poison. By then, the population of arctic foxes had dropped to an estimated 1,000 to 1,300 individuals.

With the threat of poison eliminated, Iceland’s population of foxes began to recover in the 1970s. But the biggest win for the country’s oft-maligned predators came when Iceland established its first Ministry of the Environment in 1990. By 1994, the new Ministry had developed the first legislation to offer protection to arctic foxes: The Protection and Hunting of Wild Species Act. Today, hunting is still the main cause of mortality for Icelandic foxes; nearly half of all adults fall prey to hunters each year. But now, hunting licenses are required to shoot arctic foxes; poisoning is still prohibited; and fox populations are carefully monitored. There are an estimated 8,000 arctic foxes in the country today—and in some areas, like Hornstrandir, the species is clearly thriving.

Despite the tremendous pressures they’ve faced, arctic foxes have not only persevered, they’ve shown a surprising capacity to bounce back when protections are put in place. Surely the species’ opportunistic tendencies, cleverness, and ability to adapt to extreme and highly variable environmental conditions have contributed to its success. For example, although the winter coats of arctic foxes in many regions of the world are bright white, in Hornstrandir, especially along the coast, as many as two-thirds of the foxes wear a very different color. Rather than trading their dark brown summer fur for white, a large portion of the population here has evolved to grow a winter coat typically described as blue-gray, which closely matches the volcanic sand that remains exposed throughout the winter here.

Now, with climate change knocking—and warming the Arctic twice as fast as the global average, according to some estimates—the arctic fox’s demonstrated ability to adapt may be more important than ever. How will species respond as climate change transforms the Arctic, introducing new organisms from the south, pushing others farther north, and of course melting glaciers and sea ice? While there are many open questions, the arctic foxes of Hornstrandir may provide scientists with a small window into this future world. And for at least one resilient species, it may not all be doom and gloom.


Erlend Haarberg

Erlend Haarberg was born in Norway and trained as a biologist. He has been working as a freelance nature photographer since the early 1990s, specializing in Nordic wildlife. He has won several prizes in competitions worldwide, including the 2017 GDT European Wildlife Photographer of the Year. He has also been awarded Norway’s Nature Photographer of the Year six times between 1986 and 2000.

Orsolya Haarberg

A landscape architect by training, Orsolya Haarberg turned her passion for photography into a profession when she moved from Hungary to Norway in 2005. She has won the prestigious Natural History Museum Wildlife Photographer of the Year and has twice been awarded the Hungarian Nature Photographer of the Year. She specializes in photographing landscapes and wildlife in the Nordic countries. The collective work of Orsolya and her husband has been widely published in National Geographic, GEO, BBC Wildlife Magazine, and others.

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