I’ve been lucky enough to guide several polar bear viewing expeditions to Svalbard in the European high arctic. It is a wildly isolated and beautiful place. The amazing polar bear shots that Jenny Ross captured with her camera jolt us into thinking about the many hidden implications of climate change. So often we’re drawn to the big picture data, or the sweeping effects that our planet is undergoing – and rightly so. But I also like to dwell on the stories that bring climate change to life, through the eyes of individual animals and people. Each and every polar bear is facing increased every-day stress as a result of our warming planet. One year I saw a female and cubs on a chunk of ice the size of perhaps two football fields. It was the last ice of the season in a west coast inlet of Svalbard, and she was going to float it until it was gone.

Bottom line: polar bears need ice. And there is one reason for that – their prey need ice. Polar bears feed almost exclusively on seals, and those seals are what scientists call pagophilic (”ice-loving”). As the world’s frozen seas shrink, so do opportunities for polar bears to hunt these seals and make a living from a habitat that gets smaller every year. Some of them are forced to take extreme measures – in this case cannibalism. In 2006 I found the remains of a bear in Svalbard that could well have been the result of similar cannibalism (see picture) by desperate bears.

Polar bears elsewhere face similar pressures. Their future was never far from my mind when we filmed polar bears for Bears of the Last Frontier in northern Alaska. The Southern Beaufort Sea population is looking at a questionable future – sea ice will decline there by 6% per decade over the next 45 years. We stand to lose two thirds of the world’s polar bears by the year 2050 due to the effects of climate change. That’s 16,000 bears in 40 years, or an average of more than one bear every day. Although difficult when it comes to the future of the polar bear, I like to dwell on the side of optimism. This century’s polar bears will persist for longest in the high arctic archipelago of Canada and northern Greenland – a high latitude refuge for these super-specialists. They will exist in much smaller numbers than they do today, but my hope is that they will provide a constant reminder – as well as a beacon of hope – to do right by our environment, and ultimately to do right by ourselves.

Pictured: Chris Morgan with a polar bear skull in Svalbard. (Credit: Ellie Van Os)

The Arctic is changing. As temperatures slowly rise and the ice recedes, the shore is getting further away. Food sources that the polar bear have come to rely on are becoming less plentiful. In this changing climate, the polar bear is already showing signs of distress.

While polar bears struggle, opportunistic grizzlies fare well, as they benefit from the melting Arctic’s effects on its ecosystem. While the grizzly moves into newly opened territories, the polar bear can only wait for the freezing of its one-time kingdom. If the changing world proclaims the grizzly the new king of the Arctic, what will become of the polar bear?

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Online content for Arctic Bears was originally posted February 2008.

Chris Morgan travels to the far north of Alaska, the tiny North Slope town of Kaktovik. It’s early November and winter is coming on. But each year, the polar bears struggle for extended periods on dwindling fat reserves, waiting for the opportunity to hunt on sea ice that takes longer to freeze. In early spring, Morgan joins local hunters in Barrow, the northernmost city in Alaska, as they go out on their own hunts, facing some of the same challenges as the bears. In late spring, Morgan travels to the North Slope of the Brooks Range, where countless thousands of caribou cover the ground for miles. The grizzlies are waiting for them, as they have for thousands of years.

There’s no doubt the Arctic is warming. In fact, this extreme region has warmed faster than any other on earth, with the Arctic temperature increasing three to five times faster than the Earth as a whole over the past 100 years. Climate models predict that the Arctic will become an additional 7 to 12 degrees Fahrenheit warmer during the next century.

Experts predict these rising temperatures are likely to cause the melting of at least half the Arctic sea ice by the end of the century. Melting ice is expected to lead to even higher Arctic temperatures as bright white ice plays a significant role in reflecting the sun’s radiation. As ice melts, more of the dark ocean and land are exposed to absorb the radiation, thus further warming the climate. Research has found that over a major portion of the ice-covered Arctic Ocean, sea ice is 40 percent thinner than it used to be. And some climate models predict that by 2070, there may be no summer ice cover in the Arctic at all.

The disappearance of sea ice is a particularly dire threat to the polar bear, a super specialist in the Arctic environment. Polar bears rely on the ice to hunt seals, their main food source, and also to rest between hunts out on the ice. Trapped, drowning and starving bears have become such a concern that in September 2007, the U.S. Geological Survey (USGS) released a series of studies that led its scientists to conclude that “future reduction of sea ice in the Arctic could result in a loss of two-thirds of the world’s polar bear population within 50 years.” As sad as such a fate for this majestic creature would be, the consequences would extend far beyond the bear. A polar bear decline could trigger what biologists call a “trophic cascade,” or a complete uncoupling of the Arctic food chain.

As much attention as the effects of melting sea ice on polar bears has drawn of late, it is important to understand that the thaw will have immediate effects on everything in the marine food chain, from benthic invertebrates to marine mammals. What will be the fate of the ringed seal, bearded seal, bowhead, beluga, and walrus — all creatures that depend on the ice for habitat or food?

Warming not only affects sea ice, it alters the Arctic’s terrestrial landscape. Melted permafrost means a proliferation of low-lying shrubs. These northern-spreading shrubs establish a new order of plant life, shading out low-growing lichens and plants like ground willow and cotton grass, all favorite foraging items for grazers like caribou. Without their main summer and winter foods, caribou are vulnerable to starvation.

Another species affected by changing Arctic vegetation is the lemming. Drastic changes in its food supply of sedges and mosses, along with a lack of snow tunnels to burrow in, will challenge the survival of these rodents and may cause their populations to crash beyond repair. When lemming numbers drop, so do the numbers of predators like snowy owls and Arctic foxes. Researchers have already observed warning signs in the Arctic fox population in the form of an invasion of red foxes into the traditional range of Arctic foxes.

With a warming Arctic comes an earlier spring and a proliferation of parasitic insects such as flies and mosquitoes. For Arctic dwellers as disparate as caribou and guillemots, a population explosion of insects is at best a nuisance, and at worst, life-threatening. Grazers spend less feeding time and more energy just trying to escape these pests. Arctic-nesting Brunnich’s guillemots in Canada have been such victims of relentless mosquito attack, they have been observed abandoning their nests.

A changed season for insects also has a different effect on some other species of birds, which time their migrations to coincide with insect swells. Northern Alaska dunlins, for example, migrate from Asia and lay their eggs to take advantage of peak insect populations in order to feed their young. Warmer temperatures may cause the insects to hatch earlier, throwing off the carefully timed breeding and nesting season of the dunlins.

With the Arctic experiencing the most rapid and severe climate change on Earth, the plants and animals that have evolved to survive in this extreme habitat come increasingly under threat. Like the canary in the coal mine, the Arctic can serve as our early warning sign of impending climate change. Observing the tumultuous change its inhabitants are experiencing can be a lesson to us about the changes in store for the rest of the world.

The icon of the Arctic, the polar bear, is the ultimate survivor in one of the harshest areas on Earth. Reigning over a world of ice, tundra, and snow, this carnivore would seem to have a lineage that traces back to some mammoth creature of the icy regions.

But in fact, the polar bear’s closest ancestor is a land carnivore we associate more strongly with our forests. Over the years, scientists have uncovered an evolutionary path suggesting that polar bears are a relatively new species, and actually a subspecies, of Ursus arctos, more widely known as the brown bear. Scientific evidence has found that the brown bear, a species that also includes grizzly bears, was a “precursor” to polar bears, which then went on to develop specializations for inhabiting the harsh Arctic.

Proving their genetic compatibility, brown bears and polar bears can mate and produce viable, or fertile, offspring. It is this reproductive viability that establishes that an animal belongs within a given species. In 2006, a hybrid grizzly/polar bear, which some call a “pizzly,” was discovered in the Canadian Arctic, providing researchers proof that polar bears and grizzly bears can interbreed, even in the wild. And when researchers in Alaska compared the DNA of brown bears from around the world, looking for genetic links, they made an interesting discovery about one population of brown bears in particular. Analysis of the DNA of a distinct population of brown bears living on Alaska’s ABC islands, 900 miles south of the nearest polar bear, revealed that the ABC bears were even more closely related to polar bears genetically than they were to other brown bears.

So just when did polar bears arise as a separate subspecies? Genetic models show that the emergence of the polar bear could have taken place as recently as 70,000 years ago or as many as 1.5 million years ago. For many years, a fossil found at Kew Bridge in London was considered the oldest polar bear specimen. The fossil then placed the evolution around 70,000 years ago. But recently, scientists uncovered a fossilized jawbone from an island in the Arctic Ocean midway between Norway and the North Pole, dated to be at least 100,000 years old. Scientists believe this jawbone may represent the remains of the oldest-known polar bear, thus marking the appearance of the polar bear earlier than previously thought.

Relying on the fossil record and DNA analysis, scientists have been able to arrive at a clearer picture of the polar bear’s evolutionary path over the millennia. Some 200,000 years ago, when glaciers covered much of Eurasia, the Arctic Ocean was completely frozen. It was during this challenging period that brown bears began to wander in search of food. Approximately 125,000 years ago a population of brown bears in the far north of their range was likely split off from their brown bear ancestors, perhaps because of competition for food. The population likely became isolated by massive glaciers and, while most died in the harsh environment, those bears with an evolutionary advantage — ideal coat color and thickness for extreme cold — survived and bred. Over thousands of years, this population of bears underwent further evolutionary change, adapting even more specialized traits for surviving the harsh polar environment. When life in the North demanded teeth better shaped for ripping apart seals than munching berries, the polar bear’s molar teeth changed significantly from those of the brown bear. The bears also grew white fur, which camouflaged them in their snow-covered surroundings and gave them a hunting advantage. Scientists believe that at first these bears scavenged seal carcasses that had washed ashore, and gradually began to hunt the seals by waiting at the water’s edge as the seals surfaced to breathe. This is believed to be an important step in the evolution of a new subspecies of bear — Ursus maritimus or the polar bear.

Nature once exerted such extreme pressure on the brown bear that it eventually gave rise to a new, better-adapted subspecies, the polar bear. Now, once again, evolutionary forces are acting on this long-enduring species. As the Arctic warms, the polar bear’s unique specializations that once lent it an evolutionary edge, may now be the creature’s downfall. A changing climate may name a new king of the Arctic — the fierce and opportunistic brown bear.

Considered by many wildlife biologists to be one of the most intelligent land animals of North America, bears possess the largest and most convoluted brains relative to their size of any land mammal. In the animal kingdom, their intelligence compares with that of higher primates. As highly evolved social animals, bears form hierarchies and have structured relationships with each other, sometimes even sharing resources. In fact, the polar bear, typically thought of as solitary, actually lives within a community of other polar bears and never loses track of other members.

We’ve witnessed them performing complex tasks — a sign of an ability to learn and process information. We’ve seen circus bears balance on balls, ride vehicles or roller skate, and play sports and musical instruments. Zookeepers and animal trainers consider bears to be smarter than dogs.

The bear’s cunning is legendary when it comes to guarding itself against danger from hunters and poachers. The animal’s uncanny ability to evade human predators during hunting season could almost be considered forethought. Some researchers believe that grizzlies possess self-awareness, as there have been accounts of grizzly bears covering their tracks or concealing themselves from hunters with rocks and trees.

Beyond this ursine wiliness, we find further proofs of their intelligence in their habits. Like humans, bears are omnivores. It’s well known that omnivores are often substantially smarter than more specialized feeders. Following a varied diet means that bears have to remember a great deal of information about food sources — where to find which foods and when. A grizzly’s memory is so sharp that he can remember where they encountered a certain food ten or more years earlier. And bears remember familiar animals for years, recognizing them and identifying their social status from a distance as far as 2,000 feet away.

It helps that bears are creatures of detail. They take constant inventory of their surroundings, allowing them to compile a detailed map of their territories, complete with information on where to find their preferred foods and when they can obtain them. The polar bear lives in a world of an ever-changing landscape. Hunting and surviving within an ice relief below water and on the surface demands a sharp memory.

To learn survival skills from their mother, cubs spend several years with her. She educates them about what plants are good to eat and where to find them. By the time a juvenile bear leaves its mother, it knows what plant foods are available at each time of the season, and what habitats are likely to have those foods over a very large area. That knowledge serves them well as they move into new areas, learning and remembering where new food sources are found in a new environment. This knowledge is also critical to finding food when food sources change drastically from year to year depending upon weather and climate.

In our own encounters with wild bears, we know that a bear’s resourcefulness seems to know no limits. Bears have long been engaged in a battle to figure out ways in which to benefit from living in close proximity with us. They are constantly devising new ways to get at garbage, empty birdfeeders, devour fruits from orchards and farms, clear out beehives, and open metal and glass cars to get to food that their keen sense of smell draws them to. The occurrence of polar bears scavenging in town dumps in Manitoba is on the rise. And both grizzly bears and polar bears have become more popular visitors of the dump in the North Slope town of Prudhoe Bay, Alaska. Grizzly bears in national parks have become so adept at getting into garbage bins and camper trash, that new models of supposedly “bear proof” containers are rolled out each season. New models are “market tested” with grizzlies who had to be removed from the wild because they were too comfortable around humans.

As highly intelligent and adaptable as bears are, they continue to suffer an unfortunate fate at our hands. Many bears are needlessly captured and shot because of human fear and carelessness. “Nuisance” bears, or bears that raid garbage or property, are only a nuisance when humans fail to take precautions that can keep the bears away. As humans move into territories that traditionally belong to the bears, encounters between the two will become more common. As intelligent as bears are, humans are the more advanced and intelligent species. It is our responsibility, then, to ensure that these creatures live safely within both of our worlds.

Follow as he travels to a remote Canadian outpost on Hudson Bay, where he investigates the annual invasion of hungry polar bears.

Churchill, in the Canadian province of Manitoba, occupies a spit of land that provides the fastest access onto the ice, and the bears are in no mood for any detours once the waters of Hudson Bay begin to freeze. So they congregate near the town and prowl the landscape for appetizers before the main course becomes accessible.

Ewan McGregor puts himself in the middle of the action as town and wildlife authorities skillfully cope with both the would-be marauders of the furry variety, and the throngs of tourists who descend upon the town to see the bears, often at considerable risk to themselves.

Along with McGregor, viewers get a close-up look at how polar bears that wander into town are sedated, carted off to polar bear “jail,” and eventually hoisted by helicopter onto the frozen bay. It’s a dramatic reversal from years ago, when bears invading human space often were shot, sometimes after lethal encounters with people.

Online content for The Polar Bears of Churchill with Ewan McGregor was originally posted May 2002.

Wayde Roberts is a Natural Resource Officer at Manitoba Conservation in Canada. He’s been working with polar bears for more than 10 years and in 2002 spoke to NATURE Online about his work in Churchill, known to many as the polar bear capital of the world.

What brought you to this line of work?

My family all did bush-related work, and I’ve wanted to do this kind of work ever since I was a kid. I grew up in the province of Manitoba and did a stint in Churchill working with Manitoba Conservation beginning in 1987, working for four or five straight seasons. I left the north and then returned, as an officer in Churchill, in 1996 to work with the polar bears. Basically, I’ve seen the abuse to the environment that goes on and have always felt like I’d do better by protecting natural resources than by using them.

Describe a typical day in polar bear conservation.

In typical town patrol, I’m up at daylight and patrolling with four other colleagues. There’s a control zone that’s set up, which is basically a border around the town of Churchill. If any bears pass through it, we try to capture them. When the bears move around a lot, we get very busy and may handle 12 to 14 bears before noon on any given day. Obviously, the idea is to create and maintain a separation between the bears and humans.

Wayde Roberts

Wayde Roberts

When we need to capture them, we set up a snare line, usually at the perimeter of the town dump, a place that has a lot of attractants for the bears. Then, we’ll trap them in a Culver Trap, or free-range them, meaning we’ll dart them with a tranquilizer gun. Once they’re drugged, we can keep as many as 22 bears in our holding facility before flying them north.

Have you ever had an unexpected run-in with an angry polar bear in which you felt you were in danger?

Once, when I was inside the bear-holding facility, I turned around and there was a polar bear 15 inches from me. There were a few scary moments before it ran away.

What should people do if they unexpectedly run into a polar bear — besides call you?

Well, the people in Churchill are very good and very helpful. We have a 24-hour-a-day Polar Bear alert line, which people can call to report bears that are inside the control zone. There’s a lot of education that we do, giving talks in schools and such, to try to give people the kind of information that will prevent them from getting into trouble. For example, leaving garbage out unsealed is one of the most dangerous things you can do; garbage is a natural attractant for the bears.

How do you tag the bears and what’s the purpose of doing so?

Once we tranquilize the bears, we tag their ears and give them lip tattoos with unique numbers to identify them. We’ll take a sample for DNA analysis, give them antibiotics if they have any cuts to prevent infection, and record their age if known. If we don’t know the age, we can extract a pre-molar, which the bear doesn’t need, to determine the age. With all this information, we create a “Bear Bible” for each animal. The Canadian federal government keeps all of this in a database, so we can track any individual bear’s progress from season to season.

Polar bears seem to be solitary animals. Do they not adhere to traditional family structures?

They are social animals up to a certain age, especially when you’re dealing with a mother and her young cubs, which is a dangerous kind of group to be around. Other than that, they are quite solitary.

According to some reports, the Earth’s average temperature may rise 3-5 degrees in the next 50 years, meaning the bears will have to fast for even longer before the ice freezes and they can return to hunt for food. What do you think the long-term effects will be?

As the temperature increases, the bears will have to adapt. Basically, first what may happen is that the seal population will decrease. When this vital food source is depleted, the bears will have less to feed on. Currently, though, Hudson Bay has a very healthy bear population that numbers approximately 1,200. It’s a unique population in that it’s one of the only bear populations that fast on land — they’re basically engaged in walking hibernation. The long-term effects may jeopardize the population of the great bears.

Do you think that humans and bears can continue to live harmoniously in such proximity to one another?

Oh, definitely. In fact, the mortality rate for bears because of bear-human interactions is down significantly. Now we average one bear death a year, whereas years ago, it was closer to seven bears annually. And just as importantly, from the human perspective, we have not had a bear-related human fatality since 1986. So, bears are not hurting people and people have not been hurting the bears.