Uneasy neighbours: red foxes and arctic foxes in the north

Uneasy neighbours: red foxes and arctic foxes in the north

Uneasy neighbours: red foxes and arctic foxes in the north

This article was made possible thanks to support from the Environmental Awareness Fund. Engage and educate yourself in this blog series, about Yukon Biodiversity.

15 minute read –

Once upon a time in the distant year of 2015, a Canadian wildlife photographer, Don Gutoski won Wildlife Photograph of the Year with a haunting snapshot of a red fox scarfing down the body of an arctic fox it had just killed. This grisly image titled “The Tale of Two Foxes” was heralded as a stark depiction of climate change in the north where warmer climates lead to red foxes encroaching on the territory of arctic foxes. While climate change is both a real and palpable threat to arctic ecosystems, the reasons behind the expansion of red fox ranges into the arctic and their subsequent relationship with their tiny northern counterparts isn’t that straightforward. When is it ever, am I right? Life is complicated!

Credit: Don Gutoski’s photo titled “A Tale of Two Foxes” won Britain’s Natural History Museum Wildlife Photographer of the Year 2015. It also sparked some assumptions and conversations about climate change and species competition in the changing Arctic. 

First off, it’s unfair to treat red foxes as an invasive pest freshly arrived on the arctic tundra. Historical fur harvest records from trading outposts in northern Canada show the presence of red foxes in the arctic starting in the early 20th century. In other words, they aren’t new to the neighbourhood. One of the popular hypotheses out there attributes the red fox’s northward expansion to the warmer temperatures caused by climate change. Milder winters definitely help red fox survival in their arctic home as they are nowhere near as well insulated as arctic foxes. But this balmy weather (balmy being a relative term, the arctic is still chilly as heck) is not the only factor behind their northern migration and it’s probably not even the main driving force; people are.

A study that compared the movement of red foxes with historical climate data and the development of sedentary settlements in the Canadian arctic found that it was the settlements, not the temperature, that was most closely linked to fox migration. Why? Well, it’s probably because we’re a great food source. If you live in Whitehorse, you do not need me to tell you that red foxes thrive around human settlements. It’s a fox paradise with all the garbage and unattended dog food that they can eat and a wondrous array of leather goods to steal. The fox that sleeps under my dryer vent probably feels like it has a very plush life. Quick question: It once left a decapitated grouse on my back porch; does that count as paying rent??

In a place like the arctic where resources are scarce, human settlements and by extension, human garbage (or “anthropogenic waste subsidies” if you want to impress your friends) can provide a relatively bountiful food source for red foxes. This isn’t really a good thing though. While both red and arctic foxes like to yummy down on some trash, human-created food sources favour the survival of red foxes over arctic foxes. This in turn could lead to diminished arctic fox populations in the future.

Red foxes are bigger and heavier than arctic foxes so when it comes to direct competition between the two, red foxes are more likely to be the victor. We already have grim photographic evidence of that exact scenario. Both types of foxes also have very similar diets, similar subsistence strategies (scavenging and food caching), and both of their reproductive success depends on having a den to shelter their pups. Leading very similar lifestyles put these two fox species in direct competition for resources. If this is the case, why haven’t red foxes wiped arctic foxes off the map? It’s probably because the relative survival of these two species isn’t contingent on a fox vs. fox death match. Sorry to disappoint. 

If I’m being completely candid with you, dear reader, when I was initially handed this topic, I was kind of hoping to write a shocking and grisly article about fox-on-fox violence. The carnage! The tragedy! Oh the terrible realities of nature! Not because I want bad things to happen to tiny foxes (I don’t), but because I am an absolute ghoul of a human being and that kind of content makes for a gripping article. Either way, this is not the case and I am legitimately relieved to know the arctic tundra isn’t strewn with fuzzy white bodies. Yes, red foxes do prey on arctic foxes but they are by no means out there slaughtering their smaller arctic counterparts into extinction. I mean red foxes also eat other red foxes, it’s the nature of well… Nature.

A group of researchers conducted a forty-year study of fox dens on Herschel Island and the Yukon’s coastal mainland to investigate the relative abundance of red and arctic foxes in the area. In those four decades, both of these fox populations remained relatively unchanged. We (and by “we” I really mean the researchers and biologists who specialize in this kind thing and not myself, a humble turnip and writer) don’t entirely understand all the factors that keep the balance between these two residents of the Yukon arctic. It’s a very complicated relationship and there’s a lot to unravel; here is what we know/can infer from previous studies.

Two major characteristics of the Yukon arctic that limit red fox expansion and increase the arctic fox’s competitive edge are a) limited food resources and b) the cold. As I mentioned before, red foxes are bigger and heavier which helps them bully arctic foxes away from food sources and denning sites but it also means they need to eat more. Both red and arctic foxes are opportunistic carnivores that feed on small to medium sized animals and the carcasses left behind by larger predators. While the arctic fox’s diet is largely reliant on lemmings, the red fox’s diet is more generalized which can help offset their greater need for food. But does it offset it enough? Nope.

During the winter, when food availability is at its lowest, red foxes are burning through a lot more energy than arctic foxes to keep warm. Obviously, they can survive the bitter chill of arctic winters as they’ve been up there for about a century. Red foxes can survive the winter, sure, but arctic foxes were designed for it. Not only do they need less food than red foxes, but they can drop their basal metabolic rate during the winter to conserve more energy and thus need even less food! Arctic foxes also have an incredibly dense winter coat so they need less energy to stay warm and they have a lighter foot-load (meaning they sink down less when they’re scooting around in the snow) so they burn less energy in transit. Arctic foxes are just super energy efficient, folks, I don’t know what to tell ya! While the red fox’s food and energy needs decrease their survival rates in the winter, arctic foxes can coast through it with a lemming and a box of tic tacs. Okay, that’s an exaggeration but you get the picture.

Their dietary requirements can also restrict red foxes spatially. We can see a good example of this if we look at the denning strategies of red and arctic foxes. Denning isn’t easy in the arctic: digging a burrow has a high energy cost and suitable denning sites are limited by the climate, soil type, and that ever-present permafrost. Here’s the real kicker, ideal denning areas and food rich areas don’t occur in the same place! Prime denning real estate is a high, dry area like a ridge, mound, or bank with coarse sediment, lots of sun exposure (i.e.: less frozen dirt to dig through) and low snow accumulation. This setup provides foxes and their pups with protection from the elements, predators and they’re less likely to get snowed in.

Food rich areas, on the other hand, are low, wet places like stream valleys where a higher yield of plant life results in a higher number of delicious rodents. Essentially the complete opposite of the ideal denning area. Great. Foxes then have to make a choice: choose a den with more protection from predators and the weather or choose a den closer to your food? Clearly, the red foxes with their greater need to feed are going to pick the den that’s closer to the buffet. Red foxes often move into dens dug by arctic foxes so they’ll effectively push arctic foxes out of these areas. However, arctic foxes have more flexibility when it comes to denning since they have lower food requirements. When red foxes and arctic foxes are occupying the same area, arctic foxes will prioritise dens with great predator protection and lower food density. When red foxes aren’t around, arctic foxes will favour dens closer to food rich zones instead.

With all this considered, the effects of climate change should have increased the red foxes dominance of the tundra. Warmer winters decrease the arctic fox’s advantage over red foxes and warmer weather increases the amount of plant growth and, in turn, the amount of rodent-based food sources. However, this hasn’t happened. Why? Researchers believe that the answer to that also lies in climate change and the food-related limitations of the red fox. Seal carcasses left behind by polar bears are a really important food source for foxes in the arctic. The warmer temperatures caused by climate change are reducing the ice sheets, increasing the ice-free season, and changing the patterns of seasonal ice flow. All of this is putting stress on polar bear populations and stressed polar bears likely lead to fewer seal kills and thus fewer seal carcasses. Climate change giveth, climate change taketh away, I guess.

It’s also been noted in Sweden and Norway that global warming is actually dampening rodent reproduction rather than increasing it. The resulting drop in the rodent population is having a negative impact on the arctic fox populations in these regions. If the same is true in the Yukon, it would have an even larger negative effect on red foxes due to their greater resource needs. Unfortunately, we’re lacking long term data on rodent populations in the Yukon so we don’t know if this is the case or not.

This complicated web of physical needs, adaptations, and environmental factors have led to this not entirely understood balance between two fox species and who knows which ways the scale will tip in the future. There is one thing I can tell you for sure though: previous studies have shown that an effective way to increase or reduce red fox populations is the addition or removal of human-related waste. This isn’t so much an issue in the mostly-vacant Yukon arctic but in other arctic regions with mining or oil drilling operations, it poses a potential problem. Red foxes aren’t a horrible invasive species laying waste to adorable arctic foxes but a garbage-induced boom in red fox population could negatively impact their little arctic counterparts. So clean up your garbage, don’t feed foxes, and rest a bit easier knowing that while climate change is messing up the arctic, at least it’s not inducing a fox war up on the tundra. It’s really more of a muted territorial scuffle.

Joelle Ingram

Joelle Ingram

Human of Many Talents

Joelle is a former archaeologist, former wildlife interpreter, and a full-time random fact enthusiast. She received her master’s degree in anthropology from McMaster University. One of the four people who read her thesis gave it the glowing review “It’s a paper that would appeal to very specific group of people,” which is probably why only four people have read it. Her favourite land mammal is a muskox, her favourite aquatic mammal is a narwhal. She thinks it’s important that you know that.

867-456-7400
 info@yukonwildlife.ca

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The Animals are Quite Fine Outside

The Animals are Quite Fine Outside

The Animals are Quite Fine Outside

5 minute read –

After a beautiful, drawn out fall (by Yukon standards), winter arrived in force at the end of October 2020. Record setting snowfall on November 2nd 2020 kicked winter into full gear. Shutdowns were widespread (including here at the Preserve). It was snow joke!

Now that we’ve dug ourselves out, we can offer winter wildlife viewing at its finest! Without leaves on the trees and a beautiful white backdrop, its easier to spot the animals (although the Arctic Foxes can be a bit tricky with their white winter coat). It is especially satisfying to watch animals in their element.

We sometimes get asked if we bring them inside when it gets cold. Apart from the obvious challenges of convincing the Mountain Goats to come down off their cliff, I think they all might get a little hot if they had to be inside. I don’t even want to think about “musk”ox in an enclosed space. And the Bison probably wouldn’t listen to us, even if we asked nicely. Anyway.

They are quite fine outdoors. If you’re not convinced, I give you:

 

Exhibit A: Muskox and Caribou

Muskox and Caribou were wandering around with mammoths on the Beringian steppes during the last ice age. (For better or for worse, the giant beavers didn’t make it). The Preserve’s other ice age animal (and unofficial 13th species) the ground squirrel is much more sensible. They are currently napping right now instead trying to eat each other. While there’s been a lot of snow so far, it’s probably not as much as they had last ice age.

Rebecca spotting deer, in layered clothing to blend into the vegetation - Cora Romanow

Exhibit B: Arctic Foxes.

They also get around the north (quite fine, thank you very much). Incidentally, they may be illegally immigrating into Canada from Norway. This is probably because they are the bomb. By which I mean “Among mammals, the arctic fox has the best insulative fur of all.” In the same paper, they also note that Arctic Foxes don’t start shivering until somewhere below -40c. They’re not quite sure how cold it needs to get, because the scientists that tried, “…did not succeed, because they did not have the necessary equipment available to reach sufficiently low ambient temperatures.”

This Arctic Fox is not only warm, but also enjoying a pumpkin filled with meat treat. No tricks here.

Exhibit C: Mule Deer.

Now stay with me. I realize I’m skipping past a few animals to get to what is arguably the least “winterized” animal at the Preserve. Their large ears and delicate hooves say “I’m new here”. And that’s true – they were first sighted in the Yukon in the 1930s and 40s.

What’s so remarkable about Mule Deer is just how wide a range they now have. Several years ago I was camping in the dessert outside Phoenix, Arizona. And believe it or not, there were Mule Deer wandering around between the prickly pear cactuses! Meanwhile they are now seen as far North as Dawson City, Yukon!! They are simply remarkable animals (Rebecca will back me up on this) that deserve a lot more credit than they get.

And finally,

Exhibit D: Humans

It’s really just us that get hung up about the cold. Last January I had an excellent opportunity to  to make a questionable life choice and strip down to a thin long-sleeve shirt while standing beside a caribou at -35c. I decided to leave my pants on as well as my long underwear not to mention my wool snow pants. Even so, it was quite cold. Painfully cold. Luckily Josh Robertson, a PHD student studying animals with thermal cameras had his camera handy:

The bright yellow bits in the second image are all my heat escaping out into the atmosphere. The caribou is busy eating and clearly doesn’t care. (If you found this foray into thermal imaging unsatisfyingly brief, you’re in luck, we’ve got more on this in the works)!

The animals have got this.

If you haven’t experienced these Yukon species in their element, I highly recommend a trip to the Preserve. If you’re worried about the cold I recommend:

  • Walking (shivering is a metabolic way of warming your core temperature, but walking is a way more effective).
  • Bring some snacks (to fuel your internal furnace).
  • Wear warm clothes (and you know… maybe don’t strip down to pose with animals). Soft soled boots keep your feet flexing and therefore warm. A warm hat keeps the heat from leaking out the top.

I got around a couple days ago and took a few photos to give you a taste of what you’re missing out on! Click for bigger versions – and see if you can find any of the Preserve’s bigger “cats”.

Jake Paleczny

Jake Paleczny

Executive Director

Jake Paleczny is passionate about interpretation and education. He gained his interpretative expertise from a decade of work in Ontario’s provincial parks in addition to a Masters in Museum Studies from the University of Toronto. His interests also extend into the artistic realm, with a Bachelor of Music from the University of Western Ontario and extensive experience in galleries and museums.

867-456-7313
jake@yukonwildlife.ca

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Arctic Fox Adaptations in 360 Video

Arctic Fox Adaptations in 360 Video

Arctic Fox Adaptations in 360 Video

4 min video – watch in either English or French – 

Surviving in the North is not for everyone. Those who make it need more than strength and endurance, they also need the ability to adapt to a challenging climate! Arctic Foxes are well-adapted to their frozen home in many ways. To learn more, watch this curriculum based video for schoolkids of all ages, then check out our website!

As you can see, the Arctic Foxes here at the Yukon Wildlife Preserve still have their winter coats on, but take a look at their muzzle for darker bits of fur showing through – that’s a sign they have begun shedding their winter coat.  These foxes might look cute, but they have also adapted to thrive in a really tough environment.

Survivre dans le Nord n’est pas pour tout le monde. Ceux qui survivent ont besoin de force, d’endurance et de capacité à s’adapter à un climat difficile! Les renards arctiques sont bien adaptés à leur habitat froid de plusieurs façons. Pour en apprendre plus sur les renards arctiques, regardez cette vidéo pour les étudiants – de toutes âges et visitez notre site web!

Education Team

Education Team

This 360 video is brought to you by the hard work and creativity of the Education team at Yukon Wildlife Preserve.  French translation for 2020 has been provided by Anna Tölgyesi.

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Cute But Tough – The Arctic Fox

Cute But Tough – The Arctic Fox

Cute But Tough – The Arctic Fox

6 minute read – “Winter Is Here” series continues with a species well suited to cold conditions – Arctic Fox!   

The Arctic Fox is super cute, we all agree, but don’t be fooled by its appearance, this is one tough cookie! Often referred to by scientists as Chionophiles, meaning ‘snow lover’, it is one of only a few species that have adapted1Watch our 360 video on Arctic Fox Adaptations to thrive in the harshest of winter conditions and survive some of the lowest temperatures on earth, living year round in the Circumpolar arctic. So, how does this cute, yet tough, canid survive such an environment?

Wearing its winter coat of white, the Arctic Fox can easily be mistaken for a small mound of snow. In fact, they are so well camouflaged, visitors to Yukon Wildlife Preserve often have a hard time recognising one when it is only a feet away from them. The thick white tail covers the dark eyes and nose allowing the animal to almost disappear against the snowy background. The tail further acts to wrap around the body or cover the face for added insulating protection, whilst thick fur on the paws provides protection from the snow and ice and increases grip on slippery surfaces. As well as the ability to camouflage itself for protection against predators, the white colour is thought to have better insulating properties, with greater air pockets than coloured hair to trap body heat.

The depth of the fur is 200% greater in winter with a dense undercoat of 8 lbs and an estimated 20,000 hairs per cm2.  In comparison, humans have a range of approximately 124-200 hairs per cm2.

The Arctic Fox is not always fluffy and white, though. They shed their winter fur to a sleek summer coat, and are the only member of the Fox family who sheds to a different colour, making them quite unique. Instead of a thick white fur, they spend the arctic summer a colour-blend of browns and greys – allowing them to continue camouflaging to their environment year round.

Arctic Fox is the only fox that sheds its winter coat to a different colour, allowing them to blend in to their environment year round.

A compact predator with small ears, a short snout, neck and legs, the Arctic Fox is much smaller than the Red Fox. This physical adaptation provides a low surface area to volume ratio which means there is less surface area from which to lose heat. This is one of the reasons that Arctic Fox will curl into a ball when resting – by reducing the exposed surface area, energy loss is less and heat retention is maximized. Front and hind legs are tucked underneath the body, exposing to the frigid air only the thickest, and warmest fur. The head is placed on the front paws, and the tail wraps around the face. Arctic Foxes are able to slow their winter basal metabolic rate to around 25% less than in the summer. These adaptations allow them to withstand brutally cold temperatures either curled up on the snow or taking shelter in an existing den under the snow pack. This also helps them to survive longer without food; important when food is scarce in the dead of arctic winter.

Keeping the blood flowing to the extremities is clearly important to an animal who spends its winter on the snow.  The Arctic Fox has adapted its blood flow through its legs and paws for ultimate comfort and for thriving in such harsh winter conditions. This impressive heat conserving adaptation is called the countercurrent heat exchange.

To understand how this works, let’s first look at what happens without the adaptation – in species like humans. Warm blood from the heart courses down the leg straight to the feet. If those feet are standing on icy-cold ground the warm blood will cool quickly and lots of energy will be used to keep the feet as warm as the body. This cooled blood then returns straight to the heart to be warmed, requiring more energy and resulting in an overall lower body temperature.

Source bio.miami.edu/dana/360/360F18_9c.html

Instead, this physiological adaptation in a species such as the Arctic Fox means that the vein and artery in the leg run very close together allowing warm blood going to the foot to heat up the cold blood returning from the foot. In a nutshell, the warm blood heats the returning colder blood that’s heading back up to the heart, and in exchange, the colder blood cools the warmer blood going to the feet. This means the feet are constantly cold, but just warm enough to keep the tissues from freezing. As a result, the overall body temperature is warmer, thanks to this neat energy-efficient system.

Omnivorous diets, meaning that both meat and plants are consumed, help keep the Arctic Fox adaptable to changing conditions. They are carnivorous in that they will eat meat – hunting small rodents like lemmings, but also scavenging from the kill sites of larger predators like wolves and polar bears. Much like a domestic dog may eat carrots and apples, the arctic fox will tolerate and consume foods such as bird eggs2Watch the Arctic Foxes at Yukon Wildlife Preserve get an Eggy Easter treat, berries and even seaweed.

 A behavioural adaptation to thriving when remaining in a harshly cold environment is to conserve energy by not moving a lot when it is really cold. Arctic foxes will hunt and cache food during warmer temperatures, remembering where those caches are, so that they have snacks available when they really need them – without having to expend energy when temperatures drop.

Between the highly specialized physiological and behavioural adaptations explored in this blog the Arctic Fox is well equipped. Far from being perceived as only cute and fluffy, this is actually a tough species living where few others do. The arctic tundra in winter presents a harsh, nearly inhospitable environment, but for the Arctic Fox, it’s home.

Watch this BBC Earth video detailing the trials of a young Arctic Fox learning to hunt lemmings here!

Abi Horobin

Abi Horobin

Manager Education and Programming

Abi has led expeditions to many parts of the world and has a passion for connecting people of all ages and abilities with remote, wilderness environments and the people and the wildlife that live there. Abi moved to the Yukon from the UK having been inspired by previous canoe trips to the territory and having experienced some very special encounters with the wildlife of the north. Where else do you wake to a wolf howling 10 meters from your tent?!

867-456-7313
Abi@yukonwildlife.ca

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Arctic Fox Easter Treat

Arctic Fox Easter Treat

Arctic Fox Easter Treat

Arctic foxes eat a lot of different stuff. That’s important when you live in the arctic where there’s not always a lot of food. One of their most important food sources are lemmings. But lemming populations cycle up and down over a 3-5 year cycle.

Collared Lemmings are one of the most important food sources for Arctic Foxes. Photo via iNaturalist © Jukka Jantunen, some rights reserved (CC-BY-NC)

So believe it or not, eggs are actually a really important part of an Arctic Foxes diet – especially when there’s not many lemmings around. 

The foxes go and collect up lots of eggs from birds like Snow Geese. And then they hide those eggs away for times of the year when there isn’t much food. This is called caching. Biologists have seen individual Arctic Foxes cache more than 1000 eggs in a season. 

Snow Goose colonies in the Arctic make for relatively easy pickings for a few brief weeks each spring. Photo via iNaturalist © mortenchristensen, some rights reserved (CC-BY-NC)

So it turns out the easter bunny isn’t the only animal that likes to hide eggs!

The eggs we’re feeding our foxes today are chicken eggs – they’re actually a lot smaller than snow geese eggs. We used foodsafe dyes to get the fun colours. These eggs are a great source of nutrients. The foxes might end up eating bits of shell, but that’s okay because they are rich in calcium.

Want to dive deeper into some of the research on how Arctic Foxes rely on caching eggs? Here’s a couple of papers that inspired this post:

Prolonging the arctic pulse: long‐term exploitation of cached eggs by arctic foxes when lemmings are scarce (Gustaf Samelius, Ray T. Alisaukas, Keith A. Hobson Serge Lariviere), 2007.

Cache and carry: hoarding behavior of arctic fox (Vincent Careau & Jean-François Giroux & Dominique Berteaux), 2006.

Jake Paleczny

Jake Paleczny

Executive Director

Jake Paleczny is passionate about interpretation and education. He gained his interpretative expertise from a decade of work in Ontario’s provincial parks in addition to a Masters in Museum Studies from the University of Toronto. His interests also extend into the artistic realm, with a Bachelor of Music from the University of Western Ontario and extensive experience in galleries and museums.

867-456-7313
jake@yukonwildlife.ca

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