The arctic fox: the complete guide

The Arctic fox (Vulpes lagopus) is a small canid found in the Arctic regions. It is common in the tundra biome. Its thick fur and morphology enable it to live in extremely cold conditions. Like all foxes, it is opportunistic and adapts fairly quickly to its environment. For example, the Icelandic arctic fox has acclimatised to the absence of lemmings on the island, adopting a diet consisting mainly of birds and marine animals.

The arctic fox has always fascinated humans, certainly because of its ability to live in the Arctic. Today, it attracts tourists and naturalists from all over the world who go to observe and photograph the arctic fox in Iceland, Svalbard and Canada.

We are lucky enough to be working on this species and to be organising an Arctic fox observation tour and workshop in Iceland. Every year, in summer and winter, we take a group of passionate photographers or naturalists to meet this emblematic Arctic species.

Description of the arctic fox

The polar fox’s morphology and physiology have clearly been influenced by two factors: extreme cold and the scarcity of food.

The arctic fox is smaller than its cousin the red fox. It measures between 45 cm and 70 cm and weighs an average of 5 kg, with sexual dimorphism. However, this dimorphism seems to affect weight more than size. It is also the only canid to have seasonal dimorphism, changing fur colour between summer and winter.

The arctic fox is short-legged. Its muzzle is shorter than that of the red fox, and its ears are small and rounded. The polar fox’s body is therefore small and compact, which is why heat exchange with the outside world is limited.
What’s more, the polar fox is the only canid to have fur under its paw pads. This insulates its paws and protects it from snow and ice.
In fact, its scientific name (lagopus) comes from this characteristic. The word literally means “hare’s paw”. Lagopus is also the scientific name of the ptarmigan (rock or willow), which itself has feathers under its feet.

The polar fox’s body is protected by a thick coat of fur, which is split into two layers in winter. The inner hairs are short and very dense, while the outer hairs are longer and protect against moisture. In winter, its fur thickens by 140%!

The polar fox’s predators vary from region to region. In the far north of its range, its only predator is the polar bear. At lower latitudes, there are more predators, including grizzly bears, golden eagles and red foxes. Finally, its main predator is humans. Polar fox hunting is permitted everywhere except in protected nature reserves.

Life expectancy of the arctic fox

In the wild, extreme conditions make the polar fox’s life an obstacle course. While some individuals regularly live to be more than 10 years old, most polar foxes die before reaching their first year.
This is because arctic fox cubs have to build up layers of fat between spring and autumn, in other words over a period of three months, in order to survive their first winter. They then have to become independent and find their own territory. Under these conditions, the majority of arctic fox cubs die during the summer or first winter. Those that survive are more likely to live for several years.

In Iceland, we found that arctic foxes born near cliffs have a better chance of survival than those born on plains or near beaches. The cliffs, with their hundreds of thousands of seabirds, offer a better start for the arctic fox cubs than the beaches, where they have to make do with what the ocean throws up and small crustaceans.

Arctic fox colour morphs

The arctic fox has two colour morphs: the white arctic fox and the brown or blue arctic fox.
Overall, the blue morph represents less than 1% of the arctic fox population, despite the fact that the blue allele is dominant. This is because a white arctic fox is better camouflaged in the snow than a blue arctic fox.

There are a few exceptions, however, such as the Icelandic arctic fox, where the blue allele accounts for 70% of the total population. This can be explained by the predominance of the black colour (basalt, black sand beaches, etc.) in Icelandic landscapes and the island’s low snowfall. Blue foxes are therefore better camouflaged and escape predators more easily.
The blue morphe is dominant on other islands such as Medny Island (Russia) and Saint Paul Island (Alaska), where it has reached 100%.

There are also regional variations within the same morphe. It is not uncommon to see a very dark brown fox, a caramel-coloured fox or even a sand-coloured fox.

Eyesight, sense of smell and hearing of the polar fox

Resistance to extreme climates

The arctic fox has to withstand internal and external temperature differences of up to 100°C. Its fur is the most resistant of all mammals. It enables it to survive temperatures of -70°C.
The arctic fox also builds up a layer of fat during the short summer season. This layer provides extra protection against the cold.

The arctic fox has a very low surface-to-volume ratio, limiting heat loss. Its size and compact shape also make it easier to squeeze into tight spaces for protection. In addition, one of its physiological characteristics is to reduce blood flow to the extremities to limit heat loss.

In winter, the arctic fox reduces its core body temperature and metabolic rate. This enables them to survive for several days without food. This is how it manages to travel long distances, sometimes through areas where no prey is available.

The arctic fox’s fur changes with the seasons. These changes enable it to maintain its homeothermy without having to increase its metabolic rate, but also to improve its camouflage (by changing colour).

Finally, in addition to its morphological and physiological characteristics, the arctic fox does everything it can to protect itself from extreme conditions. It does not hesitate to seek refuge when temperatures are low. It frequently uses the natural barrier to protect itself from the wind. Its thick tail enables it to protect its head by curling up into a ball. You only have to look at the arctic fox on the tundra to see this protective behaviour.

Arctic fox behavior

Diet

Talking about the Arctic fox’s diet would be like talking about a human’s: it depends greatly on the region and the individual. Foxes in general are opportunistic animals, adapting to their environment and taking advantage of the slightest opportunity. They don’t hesitate to take advantage of other species, such as polar bears or humans, to find food.

In inland regions (Russian Arctic, Canada, Scandinavia, etc.), Arctic foxes feed mainly on lemmings. It supplements its diet with birds (ptarmigan, grouse, etc.) and reindeer carcasses. The Arctic fox is both a predator and a scavenger.
As rodent populations fluctuate, foxes adapt by changing their diet every 3 to 5 years.

In summer, Arctic foxes take advantage of migratory birds such as geese to supplement their diet. They eat both eggs and chicks.

In coastal regions (Iceland, Svalbard…), Arctic foxes have more options. They consume mainly seabirds and carcasses washed up by the ocean (seals, cetaceans, etc.). For example, we have had the opportunity to observe Arctic foxes consuming dolphin and seal carcasses in Iceland. This puts them in competition with other scavengers such as the common raven.
Coastal populations also feed on marine invertebrates. Arctic foxes can almost always be observed at low tide. They scour the shoreline, turning over pebbles and small rocks to find food.

Reproduction

Depending on the region, arctic foxes mate between late February and May. Gestation lasts just over fifty days, and the cubs are born between late April and early July.

For arctic foxes, the seasonal window for reproduction is very short. But they have adapted to this constraint by growing very quickly (a minimum of 30 grams a day).
Arctic fox cubs are weaned after 10 weeks and become independent at 3 months (compared with 5 to 6 months for red foxes). On the other hand, they do not reach sexual maturity until 10 months, as is the case for the red fox.

The size of arctic fox litters also varies widely. For example, Icelandic arctic fox litters vary from 3/4 to 11/12 pups, depending on the year and breeding area. A record 19 fox cubs have been observed on Wrangel Island in Russia.

Arctic foxes use dens to protect their young from the elements and predators. These dens are used from generation to generation over several centuries. In Canada, for example, the average lifespan of a den is 330 years.
Den-building areas vary from region to region. Arctic foxes generally prefer elevated areas and avoid flood-prone zones. In so doing, they also avoid permafrost layers.
On islands such as Svalbard and Iceland, however, foxes seem to prefer rocky areas. In Iceland, dens are almost always located under rocks and/or on cliff edges.

Social behavior

The social foundation of the arctic fox is the breeding pair. They form pairs that defend a territory and raise their young together. The female initially nurses the young exclusively, while the male hunts and brings prey to the den. Later, both parents take part in hunting and feeding.
Sometimes, young arctic foxes from previous litters may stay in the territory and help raise the cubs, forming small family groups.
Pairs of arctic foxes can stay together, defending a territory and using the same den for up to 5 years.

Arctic foxes defend home ranges ranging from 5 km² to 125 km², depending on the availability of prey. While they are rather tolerant outside the breeding season, they become very aggressive towards intruders as soon as spring arrives.

We probably only know a tiny part of the arctic fox’s social life. In 2018, for example, we observed a family of arctic foxes whose parents were both white morphe. This family had 9 cubs: 8 white morph cubs and one blue morph cub. However, this configuration is genetically impossible, as the blue morph represents a dominant allele, and the white a recessive allele. In other words, there can be no brown and white fox cubs in the same sibling.
The only explanation we found was that the brown fox cub came from another family, and was adopted by the white fox family. And indeed, a den occupied by blue foxes was only 100m away from this white fox family.

Arctic fox distribution and habitat

Today, the arctic fox’s range includes Greenland, Iceland, Svalbard, Russia, Canada, Alaska and, to a lesser extent, Norway, Sweden and Finland.
But the arctic fox’s range has evolved over the ages. During the last glacial maximum, it was present at the edge of the ice, in the Netherlands, Poland and Germany.

The global arctic fox population fluctuates from year to year, depending on climate and prey cycles. But we can affirm that the population is in the hundreds of thousands. The following table shows arctic fox populations by country. These figures, which can be considered as an average, were presented by Anders Angerbjörn of Stockholm University and Magnus Tannerfeldt of the Swedish Research Council Formas.

According to recent figures, there are between 630,000 and 900,000 arctic foxes in the Arctic, depending on the year and fluctuations in lemming populations. A cycle that lasts four years and results in the collapse of rodent, and therefore fox populations.

Finally, in terms of latitude, the arctic fox’s distribution extends from the southernmost tip of Hudson Bay, at 53°N, to northern Greenland, at 88°N.

Tundra, home to the arctic fox

Tundra is one of 14 terrestrial biomes. It represents 6% of the Earth’s land surface, or around 8 million square kilometers. Most of this land is concentrated around the Arctic and Antarctic poles, but tundra is also found in the mountains, notably in Europe’s Alps and almost all of Norway.

All plant and animal species present in the tundra have developed strategies to survive in this environment.
Plants form low, dense mats, their stems are often hairy and their seeds protected by various forms of envelopes.
Some animal species have specialized and developed unique abilities. The reindeer (or caribou in Canada), for example, has specialized in the lichen it finds under the snow in winter. The absence of competition is a guarantee of survival for the species. What’s more, the lichen ferments in its rumen, generating heat and enabling it to maintain its temperature without physical activity (and therefore without expending energy).

The tundra is also characterized by a very short summer season, with average temperatures below 10° from June to August. Maintaining these temperatures is essential to the arctic fox’s survival. Unfortunately, record temperatures are regularly recorded in the Arctic.

The arctic fox occupies exclusively the tundra biome, and largely the Arctic tundra. Historically, however, the arctic fox’s range also extended into the alpine tundra. Today, only a few individuals remain in the mountains of Norway and in Swedish and Finnish Lapland, where attempts at reintroduction have been made with little success.

The arctic fox is an essential species for the tundra, as it regulates rodent populations, disseminates seeds and fertilizes the soil.

The fox’s impact on its immediate environment

The arctic fox is considered an ecosystem engineer in the the tundra.
Indeed, foxes establish their dens mainly in areas of low plant productivity, in other words, areas with poor soils. Several studies have demonstrated the positive impact of arctic fox activity on the dens’ immediate environment.

Researchers have studied both plant productivity and greening rates in arctic fox dens. In both cases, they found that fox activity favours vegetation. In summer, the amount of nitrogen present in the soil is 70% higher, and that of phosphorus is 1195% higher.
These effects are maintained over the long term, even beyond the foxes’ lifespan.

However, there are no studies to speak of on the ecosystems created by arctic fox activity. Unanswered questions include the following:

• Are there any plant species that have specialized in arctic fox ecosystems?
• Are there any animal species that benefit from arctic fox ecosystems?
• Does the presence of these green oases have an impact on the ecosystems in their immediate vicinity?

In Iceland, such oases are not uncommon, with taller vegetation and a high density of plants such as Angelica. The Hornstrandir nature reserve, where arctic foxes benefit from abundant food (seabirds), is a good example.

Subspecies of arctic fox

A subspecies is a group within a species that has acquired its own genetic characteristics. This classification lies between species and variety. Individuals of a subspecies can reproduce with individuals of the species on which they depend, or with individuals of another subspecies.

In the case of the arctic fox, we probably don’t know all the subspecies that exist, but four have already been described:

• Icelandic arctic fox, Vulpes lagopus fuliginosus
• Bering Islands arctic fox, Vulpes lagopus beringensis
• Greenland arctic fox, Vulpes lagopus foragoapusis
• Pribilof Islands Arctic fox, Vulpes lagopus pribilofensis

These four subspecies live on islands of varying sizes. They are therefore isolated from other arctic fox populations. For example, outside the ice age, the Greenland arctic fox is unlikely to encounter the Icelandic arctic fox.

Nomadic arctic foxes

We had no idea of the territories covered by arctic foxes, and we were far from imagining the results that were published in 2019 by the Norwegian Polar Institute. Researchers Eva Fuglei and Arnaud Tarroux fitted an arctic fox from Spitsbergen (Svalbard) with a GPS tracking devices before the dispersal period (when young foxes set off in search of a territory).
Researchers were able to track this arctic fox, which left Spitsbergen on March 26, 2018 and reached Ellesmere Island in Canada 76 days later. The fox then covered 3,506 km. This is the longest crossing ever recorded for an arctic fox.

The arctic fox travelled at an average rate of around 46 km per day across pack ice and glaciers.
By passing through northern Greenland, at a latitude of 84.7°N, it reduced the distance it had to cover.

The arctic fox studied by the Norwegian Polar Institute was blue in color, more suited to the southern Arctic coastal regions and marine resources. By settling on Ellesmere Island, she shifted her ecosystem to a food web that included lemmings.

This study provides an excellent basis for the reintroduction of arctic foxes to continental Europe. For the moment, this reintroduction has failed because the foxes are not genetically resistant enough. It has to be said that they are still dependent on humans for food.
With greater genetic diversity, Norwegian arctic foxes would be healthier and better equipped to cope with periods of rodent shortage.

Competition between red and arctic foxes

The question is still open to debate: does global warming favor the red fox to the detriment of the arctic fox?
In fact, the red fox is being observed further and further north, in areas usually occupied exclusively by the arctic fox. But the answer is not so obvious. While many wildlife photographers and naturalists have highlighted the predation of arctic foxes by red foxes, some studies tend to show the opposite. Canadian and Quebec researchers Daniel Gallant, Brian G. Slough, Donald G. Reid and Dominique Berteaux studied the occupation of arctic fox and red fox dens in the northern Yukon over 4 decades. Despite the fact that the study area is experiencing the most significant climate warming in North America, den occupancy appears unchanged.
Their conclusion calls into question the hypothesis linking global warming to the expansion of the red fox.

Further studies on both species are currently underway. The question remains an important one, because if researchers can demonstrate a correlation between global warming and the expansion of red fox territories, the monitoring of these two species – the red fox and the arctic fox – would become a good indicator of global warming.

On the other hand, the question does not arise on North Atlantic islands such as Svalbard or Iceland, where the red fox is absent. The Icelandic arctic fox knows no competition or predation, except from humans.

The impact of global warming on arctic foxes

Firstly, we know that global warming will have a major impact on the distribution and abundance of plant and animal species. Secondly, we know that the Arctic is one of the regions where global warming is most significant. Finally, as the arctic fox is a mammal that depends exclusively on the tundra, the decline of this biome at the expense of boreal forests (the taiga) would also cause the disappearance of the arctic fox’s unique habitat.

However, we have very little information on the impact of global warming on the arctic fox in the short to medium term. It is therefore too early to draw definitive conclusions on the subject. Nevertheless, we will enrich this section with the publication of new studies on the subject.

Conservation status of the arctic fox

The International Union for Conservation of Nature has given the arctic fox the status of Least Concern. In other words, the arctic fox is not a threatened species. However, this status is global and does not take into account regional particularities. In Europe, for example, the arctic fox is endangered (around 200 individuals spread over Norway, Sweden and Finland). Finland has even classified it as critically endangered.
The arctic fox population on the Medny Islands is also in serious danger, as a result of the ear mange epidemic. Today, only around a hundred individuals live on the island.

During the 20th century, the fur trade threatened arctic fox populations throughout the Arctic. In the 60s and 70s, when activity peaked, Russia slaughtered over 100,000 arctic foxes in some years, Canada over 68,000 and the USA over 17,000. This trade was the main source of income for many Inuit families. The collapse of the fur market has gradually led to a decline in the hunting of arctic foxes for their fur.

Taxonomy

The arctic fox is a mammal of the genus Vulpes, which includes the 12 currently extant foxes. 4 other species in the genus are now extinct.
The genus Vulpes is part of the Canidae family, which includes wolves and jackals.

Carl Linnaeus, biologist and father of modern taxonomy, was the first to describe the arctic fox and give it the name Canis lagopus. The arctic fox was then classified in its own genus, Alopex lagopus, before genetic studies definitively proved that it belonged to the genus Vulpes.

The arctic fox’s closest cousin is the kit fox, whose range is now limited to the south-western USA and Mexico. These two species diverged just under a million years ago, while the arctic fox and red fox diverged around 3.7 million years ago.

Foxes are a formidable subject of study for understanding the evolution of species and adaptations to different biomes. These 12 species are found all over the world, each with physiological and morphological characteristics specific to the biomes in which they evolve.

Origins of the arctic fox

In 2010, a Vulpes qiuzhudingi jawbone was discovered on the Tibetan plateau by paleontologist Zhijie Jack Tseng. Vulpes qiuzhudingi is an ancient hypercarnivore, now extinct, and shares many similarities with the arctic fox. A theory was born: what if Vulpes qiuzhudingi was the ancestor of the arctic fox?
This theory explores the possibility that the Tibetan Plateau, also known as the “Third Pole”, was a kind of training ground for many species that later moved to the Arctic during the Ice Ages.  This theory is called “Out of Tibet“.

This theory is counterbalanced by other studies. For example, a Russian study looked at the DNA of fossilized arctic foxes found in caves in the Urals. The scientists compared these DNAs with those of modern foxes. The results show that there is no connectivity between these two DNAs. In other words, the ancestors of arctic foxes who lived in low-latitude regions during the Ice Age simply disappeared when the Earth warmed up around 11,700 years ago. These are not the ancestors of the arctic foxes that live in the Arctic today.

The arctic fox is one of the survivors of the Pleistocene (Ice Age). Like other small mammals and birds (lemmings, rock ptarmigan, etc.), this species has found refuge in the Arctic while larger species such as the woolly mammoth and woolly rhinoceros have disappeared. In other words, the arctic fox is a survivor from a time when much of the northern hemisphere was covered in ice, and France and Spain were vast tundra.

Arctic foxes and humans

We can’t say that humans have made life easy for the arctic fox, or any other terrestrial predator for that matter. The relationship between humans and foxes has always been one of conflict and competition, often to a fault.

As the arctic fox is an animal essential to its biome, humans benefit directly or indirectly from its presence. But all over the world, human dominance and killing spree seems to be taking over, making the arctic fox (and other fox species) a prime target.

Arctic foxes, like red foxes, have always been part of human culture. Through mythology, fairy tales and beliefs, but also in the daily lives of farmers on the Arctic frontier or Inuit hunters.

Foxes have always had a place among us. If we look at foxes and humans, we soon realize that the two species are very similar: opportunism, resilience and exploration have led humans, like foxes, to colonize almost the entire planet.

In the video below, we observed a white Icelandic arctic fox regularly using an old boat as shelter from the wind and weather.

Myths and legends about the arctic fox

Arctic foxes are the main characters in many folk tales, myths and legends throughout the Arctic. This small animal has always fascinated humans with its ability to survive where humans could no longer. The Arctic fox’s opportunism also reminds us of our own behavior.

History of the arctic fox in Iceland

The arctic fox colonized Iceland during the last ice age, which began 115,000 years ago and ended 11,700 years ago. They used the pack ice to travel to Iceland, which was itself under ice.
At the end of the Ice Age, melting ice isolated it from other arctic fox populations. This is the main reason why the Icelandic arctic fox is a subspecies, having evolved independently of other subspecies.

The Icelandic arctic fox has found itself in an unprecedented situation, in a land where lemmings are totally absent. As a result, it had to adapt its diet and turn to other prey, such as seabirds and rock ptarmigan.

Seabird populations are stable in Iceland. In fact, they don’t fluctuate like lemmings in the Arctic. As a result, Iceland’s arctic fox population is more stable.

Rock ptarmigan, on the other hand, are subject to cyclical fluctuations. Inland foxes, which depend in part on this species, can therefore be affected by these fluctuations. Although, with the rise in migratory bird populations, these foxes are less and less dependent on rock ptarmigan.

Finally, although rodents were introduced by humans 1100 years ago, they are only a tiny part of the Icelandic arctic fox’s diet.

Today, more than 7,000 arctic foxes live in Iceland. The population is increasing, but remains concentrated in national parks and isolated regions. Hunting is still authorized in the country, and 56,000 arctic foxes were killed between 2010 and 2020. The Icelandic government subsidizes the hunt, which has become a profitable pastime, but many voices in the country are speaking out against the massacres and their cost.

Photographing the arctic fox

The equipment you need to photograph arctic fox clearly depends on the region. If hunting is practised in the area you’re visiting, then you’ll need hiding equipment and a telephoto lens of at least 400mm.
On the other hand, in nature reserves and other protected areas where hunting is prohibited, arctic foxes are not very shy. This doesn’t mean you can interact with them. Indeed, they remain wild animals and you need to keep a safe distance and behave responsibly to protect them. However, there’s no need to camouflage yourself in these areas – quite the opposite. Allowing foxes to identify you and know your position is safer for them.

In both cases, we advise you to use long focal lengths (600 mm is ideal) to photograph arctic foxes without disturbing them. This is what we recommend to participants in our arctic fox photo workshop in Iceland.

If you’re planning to go into dens to photograph polar fox cubs, then you need to be even more careful. The basic rules are to keep your distance from the dens and let the fox cubs approach you instead. You must never distract the parents from their objective, which is to feed the cubs. To this end, avoid positioning yourself on the paths that the adults use.

Finally, if you’re looking for an agency to accompany you on an arctic fox photo tour, don’t hesitate to contact us to discuss your requirements.