Arctic fox seem to make their living by following bears around and scavenging. We have seen foxes trailing behind bears as they travel, and their tracks often wind around bear prints. (My apologies that the pictures below are graphic. However, the carcass below illustrates a critical aspect of the life of predators).

These bones – the vertebral column and attached ribs – are all that remained of a large seal that was most likely killed by a polar bear. The area was covered with fox tracks, and the carcass had been thoroughly scavenged.

Even a flipper had been used for food – the bones of this flipper were intact, showing the similarity to the shape of my hand.

Such an existence seems precarious; polar bears range over great distances, and their successful hunts are few and far between. What if the fox doesn’t find a carcass? It turns out that foxes themselves can be successful predators of young seals. In the early 1970s, a researcher named Thomas Smith trained his Labrador dog to sniff out seal lairs (lairs are in hollow spaces on top of sea ice but below a blanket of snow; seals use these protected spaces to rest and give birth). He spent several winters digging up hundreds of lairs and found evidence that Arctic foxes were able to enter the lairs and predate on young seals. He wrote:

“A keenly developed olfactory sense allows the arctic fox to locate the subnivean seal lair, sometimes through snow depths of over 150 cm…Lairs that had been entered by foxes showed one or more entry holes. Usually the holes penetrated the lair at a slight angle and were never more than 20 cm in diameter…In the case of an apparently successful kill, blood was always present on the floor of the birth lair once the lair had been dug open…When the lair was well developed into a tunneled structure there was usually more blood and the site of the actual kill usually appeared to be in one of the small tunnels”

In fact, Smith concluded that in certain parts of the Arctic, foxes may be more important predators of young seals than bears. However, foxes were never found to kill adult seals, which must be simply too large for a fox to attack. Foxes were also more thorough than bears. They seemed to remain at the site for several days and consume the entire carcass.

So perhaps foxes don’t live as close to the edge as I originally thought, although no animal in the Arctic seems to have it easy. In a very different way, our field season is currently on the edge – due to good weather early on, we flew for more hours than were budgeted, leaving one of our two helicopters in a crunch for funding. We have scrambled to line up addition funding, to support the helicopter for more time; otherwise, we could be forced to end the season in just a couple days. We have had some tremendous luck in locating and re-sampling bears from previous field seasons, giving us great data on how bears fare over time – I really hope we are able to continue flying.

On what has become a rare, sunny day, this is my view through the bubble windshield of the helicopter, wrapping below my feet, as we fly north over the sea ice.

Thomas Smith’s article:
Thomas G Smith. 1976. Predation of ringed seal pups (Phoca hispida) by the arctic fox (Alopex lagopus). Canadian Journal of Zoology, Volume 54, pages 1610-1616.

This is the view to the north from the desk in my room at the bunkhouse. The houses and power lines of Kaktovik are visible, and the fog doesn’t seem that bad, especially given the blue sky. However, this is a “sucker hole” that can trick you into thinking that visibility is good, when in fact, you happen to just be in a hole of clarity in an otherwise thick fog bank.

This picture is from the same perspective, an hour later. The fog has mostly lifted – now, beyond the houses, a hangar (about ¾ of a mile away) and the northern horizon of sea ice are visible.

The reductions in flight time have given me time to catch up on coursework and get some reading and thinking done. Even when the schedule is very busy, sometimes the helicopter can be a surprisingly good place to think. The pilot is obviously busy during flight, and as passengers we are always scanning the ground for bear sign – tracks, kill sites, carcasses. However, once you get into the rhythm of scanning and tracking, your mind can return to the larger concepts of the project, turn over the data you have collected so far, or move onto other questions. I suppose it is similar to any situation where you put several people into close quarters for several hours of travel – interesting conversation can come up, or people can mostly travel along in their own minds.

We have been talking recently about how to interpret some of our data in regards to polar bear diet. We have months of analysis before we can begin drawing conclusions, but the summary of our data up until now can provide suggestions. One of the reasons the polar bear diet is interesting is that it is fairly simple in comparison to the closely-related brown bear (grizzly bear). Polar bears mainly eat seals, and this is reflected in their dentition, whereas many brown bears consume a wide variety of food items, including lots of vegetation.

The canine and incisor teeth of an adult polar bear. Polar bears have evolved larger canines because these stabbing teeth are useful in hunting, and polar bears hunt more than most brown bears. Polar bears also have reduced molars because they eat less vegetation than most brown bears, and therefore have a reduced need for grinding teeth.

I met up with the team of researchers from the US Geological Survey who had been performing polar bear captures out of Barrow already for two weeks. That evening, after looking over our gear and getting caught up, I went over to see friends who recently moved to Barrow from Wyoming. It was great to hear about their new life in the area; moving from the mountains to the tundra is certainly a big change.

The next day I began flying in the helicopter for captures. We started in Barrow, fueled up in Deadhorse, and ended the day in Kaktovik, near the Canadian border – we covered almost the entire northern coast of Alaska. Since then we have been based out of Kaktovik, and we have had good weather and have been flying a lot.

It is great to be back out on the sea ice. Although I am out of place here, I really love this environment. In this picture we landed on a small pan of ice about twenty miles from shore; the pan was surrounded by pressure ridges and rubble from ice sheets smashing into each other.

The captures have been going well. We caught the largest bear I have seen, an adult male who weighed 1,147 lbs (I am not sure what the largest bear caught in the southern Beaufort has weighed). His neck was several times the size of my waist, and I could not fit both hands around his snout. It took several people to position him for measurements. We have caught several bears which were sampled in 2009, giving us excellent data on changes over time in the same individual.

We have also caught a lot of cubs-of-the-year, or COYs, including this litter of three. Cubs are born around January 1st. Litters of three are fairly uncommon for polar bears in Alaska, and usually include one cub that is noticeably smaller than the others – in this picture, the cub in the middle only weighed 12 lbs, nearly 10 lbs less than the other two.

I have continued with my coursework and working on sample analysis back on campus. A full-time technician on the project has perfected several of the analyses we will perform on samples of muscle tissue, and we have had stable isotope analyses performed on breath samples.

This spring I traveled to Argentina to present preliminary polar bear data, visit field sites to discuss possibilities for research projects, and catch up with a friend from graduate school who is working there. It may seem odd to jump from polar bears in the Arctic to grazing animals high in the Andes mountains, but animals face similar challenges in both places – there is a season of good food availability followed by a season of poor availability and difficult weather, and the systems are fairly simple, with just a couple large-bodied animals dominating the landscape. I hope to return someday.

I gave a presentation on the polar bear project at the Universidad de La Plata, a national university near Buenos Aires. Many undergraduates attended, most studying Zoology and Ecology. I also presented at a provincial ecological research center and a national park.

These vicunas – grazing animals very similar to alpacas and llamas – live in the rocky environment of Nacional Parque San Guillermo in Argentina, at 10,000 to 14,000 feet. For a brief period during the summer lush grass is available in a few areas near water, but for most of the year, they forage on sparse vegetation. Their main predators are mountain lions, the same species that is found in North America.

The Arctic sea ice has had a very interesting winter. The sea ice extent was substantially below average for much of the winter and appeared to reach its maximum extent in early March, which is normal timing. However, cold weather over the Bering Sea and Barents Sea then caused the ice to resume growth, causing the sea ice extent to increase again and not reach its maximum until March 31st, the latest date since satellite measurements began in 1979 (interestingly, temperatures remained above average near the north pole). Ice extent is now very close to the 1979-2000 average.

Extent of sea ice in the Arctic, during this winter. The blue line shows the unusual growth of extent until the end of March. Image is reproduced from http://nsidc.org/arcticseaicenews/.

Although the sea ice extent is near normal for this time of the year, it is still below average. The ice which formed in March is thin, first-year ice which is very vulnerable to melt – although the extent is near average now, once warm temperatures return in the summer, much of this ice will melt. The proportion of ice which is greater than two years old and very thick continues to decline, contributing to the long-term trend of reduced extent. There is a good discussion of the current sea ice conditions at http://nsidc.org/arcticseaicenews/.

I am headed back to the field soon for our final intensive field season. It is still winter on the north slope; it is currently 1 degree (Fahrenheit) in Barrow, which will be my first stop.

One afternoon a young adult female polar bear wandered by the ship. She appeared out of the blowing snow and walked past the stern, fairly close to the ship. An hour later she reappeared and approached the ship, walking up the fantail until she was directly below the railing. Scientists and personnel from the ship were pressed at the railing above, and she just seemed to be curious, sniffing the wind and looking back at us, occasionally pawing the broken ice at the ship’s waterline.

This young adult female bear walked past the ship, eventually coming right up to the ship.

The polar bear, standing just below us at the stern of the ship.

The railing of the fantail where folks are standing is about 5 meters, 15 feet, above the ice where the bear was standing, at the aft end of the ship, the fantail. It was a wonderful chance for people to see this bear up close.

The wind finally dropped below 20 knots for a day and we flew for the bear – only to encounter heavy fog that prevented us from finding her. We located another bear that was a lower priority and we successfully captured her, yielding good data. The next day the fog dissipated and we flew for our priority bear again, but she had moved over 30 miles and we could not locate her until we received a satellite transmission at the end of the day. We remained in the area because this bear was one of the two top priority recaptures remaining, and we successfully located her twice, but both times she was traveling in large areas of broken ice which were unsafe for captures. The temperatures remained warm throughout this period, rarely dropping below 25 degrees; the water temperature remained warm as well, and sea ice simply was not forming very fast.

Poor ice near one of our priority bears.

This is a frustrating aspect of field work: success relies heavily on weather, and the bad luck of encountering stretches of poor weather can put an entire field season on hold. The only thing that can be done is planning. We planned a long field season to provide multiple opportunities to recapture each bear, and we planned on capturing secondary target bears as necessary. Thus, even though strong winds and fog really reduced our flight opportunities and poor ice reduced our capture opportunities, we had successful recaptures of target bears and we were able to process new bears as well.

The poor ice conditions we have encountered are remarkable. Air and water temperatures remained very warm throughout October, slowing the formation of new ice as winter begins. The current distribution of sea ice in the Beaufort is much more typical of late summer than early winter – we have not had to break heavy ice at all in the last 10 days. It is inaccurate to state that this warm October has been caused by climate change; climate refers to long-term patterns of average conditions, not day-to-day weather. Even in a world with an enhanced greenhouse gas effect, some autumns will be colder than normal and others will be warmer than normal. However, climate change is changing what is considered “normal.” As the earth’s climate warms, particularly in the Arctic, the type of weather we are experiencing may become common.

Graph from National Snow and Ice Data Center. Extent of sea ice over the entire Arctic is currently low compared to the 1979-2000 average, in fact, it is nearly as low as the same date in 2007, when the extent fell to a record low.

Today we disembarked from the ship, using helicopters to ferry people and luggage back into Barrow. Although the trip ended on a frustrating note, overall, it was a very exciting success. Every piece of data we gathered is unique – almost nothing is known about polar bears during this time of year, particularly bears out here on the pack ice far out at sea. I cannot wait to return to Laramie and receive data from our shore-based capture crew, which recaptured bears on the coast during the last several weeks. Before any in-depth analyses, it will be informative simply to compare data sets from the bears on ice to the bears on the coast, to see if differences are striking.

The gym is below the foc’sle, meaning it is below the main deck very near the bow. The floor in the gym slopes upward; I tried the treadmill for the first time, and decided to do a “hills” run. So, the already-leaning treadmill slowly tilted more then less, repeatedly, every one to two minutes, while I ran in place for 25 minutes. We were breaking moderate ice (probably around a foot thick) so the ship was rocking unpredictably as well, particularly when we encountered pieces of thick multi-year ice (many feet thick). By the time I stepped off the treadmill and tried to walk across the gym I was tilting pretty far myself. I walked slowly, from equipment to equipment, bracing myself as I went.

The gym is located near the bow of the ship; the bulkheads (walls) around the gym are on the outside of the hull, so the sounds of breaking ice can be incredibly loud. Last week I was in the gym when we were breaking very thick multiyear ice, and the sound was like being inside of a thundercloud. I would have had to yell to be heard by someone standing next to me, and the screeching and crunching completely drowned out my ipod. The large white tube in the corner runs from the foc’sle above to a room below the gym. The anchor chain is spooled below, where it is paid out or retrieved by a diesel powerplant up to the deck, where it hangs over the side and is attached to a 9000 lb anchor.

I have participated in other aspects of normal life aboard the ship as well. Last week I caught one of the movies shown nightly in the theatre: about 35 well-padded seats that rocked, as in a real theatre, facing a big-screen television. I got a haircut at the barbershop – there is even a striped pole in the hallway. “Pie in the face” voting took place across the ship for a week, and personnel who received the top 5 votes each took a turn sitting in a chair, surrounded by the crew, one night in the hangar. A vigorous auction took place for the right to be the person to actually sling the pie (gently; no broken noses were allowed). Last night I played bingo in the mess deck after dinner. Around 30 folks show up, once a week, and everyone plays three cards at once.

For most of my downtime I am trying to keep up with the course I am taking this fall (Biochemistry), reading research articles and preparing for an upcoming conference, and otherwise doing what I would be doing at my desk back in Laramie. Unfortunately space is fairly tight on the ship and desks are hard to come by so I do most of this work sitting on my bunk, which is just about 2 inches too small to allow me to sit all the way up.

I cannot view the dispatches myself, but it was passed on that someone asked about our rooms. Our room contains two bunkbeds (“racks”), four closet spaces (mine is visible at the right), and a chair. It is probably around 10 feet by 10 feet. The beds are narrow and long, and they lift for more storage space directly beneath the mattress. A vent in the ceiling delivers fresh air.

Recently, after the two days of transit the ship was hove to in very thick ice near Banks Island, which is in the southwestern corner of the Canadian Arctic Archipelago.

This view from the helicopter shows an area that may show up in a satellite image as mostly-covered with ice, but once we get out there and see it the ice pans are small and separated by open water, making it impossible to capture a bear.

This is the view from the portside main deck this morning, facing south. Thick, multi-year ice from the central Arctic flows south into this area, so the ice conditions are much better for captures. The ridges indicate areas where multiple ice pans have crashed together, and because they are thick pans the broken pieces stack up high where they catch windborne snow.

For captures, we need calm winds, good visibility, thick continuous ice, and a good bear location. Those factors came together to allow us to recapture an adult female we first sampled on May 8th. She was in excellent condition, carrying lots of food reserves in the form of body fat: she had about 6 cm of subcutaneous fat near her rump. All of the sampling went well, but it was slow, partially because of the cold. Temperatures were around 15 degrees (Fahrenheit) during the sampling, which took several hours. It was our first fairly cold day, and a good reminder of the difficulties we may encounter if it gets much colder. Temperatures have continued to drop; as I write, it is 8 degrees with a windchill of -11 degrees.

This 22-month old cub belonged to one the bears we recently recaptured.

This adult female had two 10-month old cubs with her. We waited in the helicopter as the bears walked past, until they got into a good position for a capture.

During June, the Arctic lost an average of 26,400 square miles of ice per day. It is normal for Arctic ice to melt throughout the summer and refreeze throughout the winter. However, the pace and extent of ice melt in the summer has increased dramatically in recent years. Precise satellite measurements of ice began in 1979. To investigate ongoing changes in ice cover, many scientists compare measurements to averages from the period of 1979-2000. For example, Arctic ice covered an area of 4.43 million square miles during June, an area that was 270,000 square miles less than the 1979-2000 average for June. In other words, there was less ice in June than in a typical year. This is representative of a long-term trend of less ice every year; since 1979, Arctic ice cover in June has declined by about 3% per decade.

This satellite image shows Alaska in the lower right and Russia in the lower left. The black dot in the center is near the geographic north pole and shows an area that has no ice data. The sea ice is falsely colored and coded by concentration. Areas with low concentration are mostly open water with little ice; areas with high concentration are mostly ice, with little open water. This image has been reproduced from The Cryosphere Today, a website of the University of Illinois. Snow and ice data provided by the National Center for Environmental Prediction/NOAA.

The gray line depicts the average extent of ice in the Arctic over the years 1979-2000. The green dashed line depicts the extent during the record year of 2007, when ice extent was the lowest on record. The blue line depicts 2009. Ice extent has been low this year, but thus far, not record-breaking low. This chart has been reproduced from the website for the National Snow and Ice Data Center (http://nsidc.org/arcticseaicenews/).

There are several online resources to track changes in Arctic ice extent. The National Snow and Ice Data Center tracks daily ice extent and provides historical comparisons and analyses. The website is http://nsidc.org/arcticseaicenews/. The Cryosphere Today is a website of the University of Illinois at Urbana-Champaign, Department of Atmospheric Sciences. This website also provides ice extent data, as well as detailed satellite images that clearly show the current ice extent.

Although satellite measurements of ice extent are only available beginning in 1979, some scientists have used other resources – such as ice charts created for shipping traffic – to piece together a longer history of Arctic ice extent. One group of scientists examined data from 1953 to 2005 and found that the Arctic ice extent in September declined by about 8% per decade (Meier et al. 2007; see citation below). In other words, on average, every year there is 8% less ice in September than the previous September. This raises the possibility that in the near future, there will be no ice in September of each year; that is, Arctic ice could completely melt every summer. That scenario would be a dramatic departure from the Arctic that we know today.

I have spent my summer mostly working on logistics and equipment for future capture work. I will return to Deadhorse on July 29th to set up our lab and prepare for August work. We will capture bears on shore and perform sampling during the first half of August. Afterwards, I will return to the University of Wyoming for several weeks. In late September our research team will travel to Barrow, which is a town west of Deadhorse on the Alaskan coast. From Barrow, we will use helicopters to board a US Coast Guard ship – the icebreaker POLAR SEA – to travel north to the edge of the retreating Arctic ice. During the month of October, we will remain at sea, launching in helicopters to recapture collared polar bears that have followed the sea ice north for the summer.

Each capture operation requires several hundred pounds of gear that needs to be sorted, packed, and shipped. Unfortunately, half of the gear that I shipped back to the University at the end of May was lost in transit. I spent a frantic three weeks on the phone, calling every shipping dock where the equipment may have gone. Finally, on the day I began purchasing replacement gear, I received a call that the equipment had shown up in Salt Lake City, Utah, and could be sent to me immediately. That was quite a relief. Now, I am back to sorting and packing in anticipation of August.

Citation
Meier, Stroeve, Fetterer. 2007. Whither Arctic sea ice? A clear signal of decline regionally, seasonally and extending beyond the satellite record. Annals of Glaciology 46:428-434.

Polar bear tracks in the snow along the Arctic coast in northern Alaska, in October 2008.

Dr. Henry Harlow, Dr. Merav Ben-David, and John Whiteman (left to right) with an adult male polar bear who has been sedated for measurements. They’re sitting in front of a temporary windbreak (to make measurements easier) on sea ice off the northern coast of Alaska in October 2008.

Summer is a critical time for polar bears and climate change is lengthening Arctic summers, which could have a substantial effect on bear populations. However, much of what is known about polar bears comes from studying them out on Arctic sea ice during late winter and spring. During summer, most sea ice retreats far to the north, leaving some bears on shore for several months. Scientists suspect that these bears face difficult conditions on land; temperatures are warm and there’s little to eat. In contrast, some bears follow the retreating ice north, where temperatures are cooler and there may be opportunities to hunt seals.

To find out how polar bears fare in the summer, PhD candidate John Whiteman and his advisors Drs. Henry Harlow and Merav Ben-David are collaborating with scientists from the US Geological Survey and the US Fish and Wildlife Service. They are capturing and examining bears in early summer and attaching GPS-tracking collars, then re-capturing the same bears in late summer and examining them again. Comparing early- and late-summer indicators of body fat, muscle, and diet tells the scientists how well polar bears are faring in summer months. Additionally, they can use this information to forecast how longer Arctic summers may affect polar bear populations.

Bringing monitoring equipment out on to the sea ice on an Inuit sled.

Many partnerships have already formed, or are forming. Some are practical—such as pairing indigenous guides who understand polar bear behavior with scientists who need bear protection. Some are more profound. For archeologist/anthropologist Anne Jensen, who often collaborates with Iñupiaq Elders, Iñupiaq people often fill in the gaps in research. In 1994, for example, the body of a young girl from about A.D. 1200 surfaced on a bluff near Barrow. Jensen was called to examine it and discovered that the girl had been buried with some pieces of skin. The Iñupiaq Elders were able to identify the skin as part of a kayak cover by looking at its shape and its stitches, drawing on their traditional knowledge.

In Canada’s Ashkui Project, Environment Canada scientists collaborate with Innu Elders to gain understanding of the area’s ecology. Here, both parties discuss the results of water chemistry tests.

Increasingly, there are more formal partnerships between researchers and indigenous people as well. For example, geographer Shari Gearheard is heading a three-year National Science Foundation–funded project in which scientists and Inuits in Canada, Greenland, and Alaska form a research team to study sea ice. According to Gearheard, scientists know relatively little about the small-scale and regional processes and changes in the sea ice, while the Inuit have a very detailed knowledge of sea ice at the fine scale. “This is useful for scientists, who study sea ice mainly from satellite imagery, so they have complimentary perspectives,” she notes.

Shari Gearheard with Ilkoo Angutikjuak, Inuit Elder and hunter from Clyde River, Nunavut, with whom she has worked closely since 2000 on environmental change research.

These partnerships are not without problems, however. For example, scientific data and indigenous knowledge can conflict, and collaborations have raised the issue of indigenous knowledge as intellectual property. Also, it’s not always easy for indigenous people to trust scientists; they’ve been burned in the past. As scientist Glenn Sheehan notes, “Local people that I know were treated with radioactive iodine in a “zany” experiment to see if it would affect their susceptibility to cold. These people did not speak English at the time, and they were not told what was happening; in fact, they were given lies. Now when some of them get cancer they are convinced, perhaps rightly, that it was scientists who did this to them.”

Despite these issues and obvious past abuse, the collaborations between scientists and indigenous people are increasing, providing a more complete picture of the Arctic and climate change than either perspective could offer alone.

The Arctic and Antarctica: Two Different Worlds

Literally on opposite ends of the earth, the Arctic and Antarctica are vast, icy, and cold, but beyond that they’re very different. Antarctica, in the south, is a continent surrounded by ocean; the Arctic is an ocean surrounded by continents. There are no native people in Antarctica (but lots of research scientists); the Arctic’s native populations stretch back for centuries. And unless you’re at a zoo, you’ll never see a polar bear and a penguin living in the same neighborhood. Polar bears live only in the Arctic; penguins live in Antarctica, and other parts of the Southern Hemisphere. Some of the major differences between the two regions are listed below.