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.

The hut which is my home away from home for several days in Barrow.

Inside, the curve of the walls stands out. I am enjoying the last couple days on shore before heading to the ship.

This morning we woke to a thick dusting of snow which did not melt as the day warmed. We are staying at the facilities of the Barrow Arctic Science Consortium, or BASC, which is a kind of clearinghouse for many research projects that are based in this area. The area also houses the North Slope Borough Department of Wildlife, and I?isa?vik College.

This bowhead whale skull stands in front of the college. Subsistence hunting of bowhead whales continues to be an important cultural feature of this area. The autumn hunt begins tomorrow here in Barrow – perhaps over 30 people will launch in small boats from the beach outside of town in the morning, seeking to find and land a bowhead whale.

Our study is the lead project on the science portion of the cruise on the US Coast Guard Polar Sea which begins tomorrow. Several other projects and a total of 24 personnel are involved in the science portion, and in the last three days, everyone has arrived in Barrow and found temporary accommodations. Tomorrow morning I will get up early and walk over to a small warehouse with a large load scale, and, hopefully, beginning at about 715am, each person will come by and we can count, weigh, and label their baggage. Two helicopters and one small boat will be used to ferry people and luggage to the icebreaker, which is planned to be anchored several miles offshore to the west. Simultaneously, 32 people and all of their luggage will be disembarked from the ship. After several meetings and rounds of organization today, the schedule seems to be on track.

Outside of Deadhorse, we drove through fields that provide oil which flows through the trans-Alaska pipeline to Valdez. Oliktok is northwest of Deadhorse, and I was told it is the farthest north you can drive in North America. Oliktok Point is a spit of land that juts into the ocean, and the US Air Force maintains a radar site for scanning the skies along the northern coast. The radar site was built during the Cold War, and is one of several such sites scattered along the coasts of Alaska.

Oliktok is much different than either Deadhorse or Kaktovik (a town farther east on the Alaska coast). The radar site is normally operated by crews of 2 people, but rooms and meals can be provided for up to 12. An oil drilling facility is just down the coast, but this area feels much more isolated. The living quarters are in a single long, narrow building that seems like a ship on the inside. All visitors here are required to watch an informational video about polar bear safety. Polar bears are frequently seen in the area and in fact, a tragic attack occurred here in 1993. A polar bear broke through a closed window to attack a man sitting in the living space. The bear mauled the man and other people at the facility were forced to shoot it. You can read the full story here. Since then, precautions have been taken to make the facility safer, such as placing grating over the windows. Such an attack is an incredibly rare event, but serves as a reminder to use caution in the habitats of wild animals.

Skies were blue and temperatures climbed into the upper 60s (Fahrenheit) and maybe even 70s our first several days here. This unseasonable heat felt odd – I expected to be wearing a light winter coat rather than a t-shirt. Yesterday heavy fog and cooler temperatures returned. Hopefully skies will clear and we will be able to fly again tomorrow. The tundra is completely transformed from May, and summer is in full bloom.

A tundra-covered island off the coast, pocked with small ponds.

A large herd of caribou, grazing near piles of driftwood on the coast.

Thus far we have caught two adult females, each with twin male cubs. It is great to see bears again. After working with polar bears last August, last October, in the spring this year, and now seeing them again in August, I am beginning to get a better understanding of their annual patterns. For example, their fur is much thinner in August and many bears are still shedding heavily. By October, their fur was deeper, and by spring the fur was quite deep with very distinct layers of coarse guard fur and thick underfur.

A large adult male polar bear, anesthetized and laying on a gray tarp for BIA analysis.

Footprints of the same male. His footprints are side-by-side and consist of two rounded prints topped with short, sharp imprints from his claws. My handprint, small by comparison, is just to the right.

Without food, it is generally thought that animals go through 3 phases of fasting. Phase I occurs directly after a meal, when an animal breaks down carbohydrates from the food for energy. In phase II, hours to days have passed since that meal. The animal begins to burn its body fat for energy, and importantly, the animal mostly avoids breaking down its protein (e.g. its muscles) for energy. Finally, in phase III, the animal runs out of body fat and begins to burn its protein for energy. These three phases are broad categories, and many animals prolong a phase or a transition between phases to survive periods without food. Polar bears in the summer may be in a prolonged phase II – we plan to find out using BIA and other measurements.

Weather has been poor this week. It has been overcast with temperatures mostly in the teens (Fahrenheit), and snowfall and ice fog dramatically reduced visibility. Some days we have not been able to fly at all; other days we launched but flew only several miles before being turned back by low visibility and icing conditions. Our helicopters are only instrumented for flight with visual references (in other words, they do not have the instruments which commercial airliners can rely on in reduced visibility) and there is no point in flying when you cannot see bears. While we wait for better weather I have been able to get other work done – and I have managed to catch the last twenty minutes of “The Incredible Hulk” movie twice, on the television in our living space. The skies began clearing during dinner this evening. Hopefully we will get out tomorrow!

On a recent capture, brief sunshine ended when this bank of clouds and snow followed us home.

This week has been very windy as well. At capture sites, we set up a wind shelter to make sampling easier. Collection bags full of bear breath are visible in the near side of the shelter.

The United States Geological Survey (USGS) has been capturing polar bears in late winter in northern Alaska for decades, and their research provides much of the current science regarding polar bears. The USGS crew that performs captures often stages out of different towns in the Arctic, including Kaktovik, to access different regions.

The city of Kaktovik, Alaska, from the air. The airstrip is in the foreground. There are no roads to Kaktovik – you must fly in, travel by ocean, or make a long journey by land through the Arctic Wildlife Refuge.

On Friday, a USGS scientist picked me up at the airstrip when I landed in Kaktovik. We returned to the bunkhouse where the crew was staying and I jumped in to help to prepare platters of cheese and sausage, a pot of chili, and lots of coffee. We brought the food down to the community center and participated in a community meeting. A scientist from USGS and me had the opportunity to meet residents and discuss research activities based in their town, activities which involve an animal many folks there know intimately – the polar bear.

The USGS crew had already been capturing polar bears for several weeks. The next morning the temperature was -20 degrees (Fahrenheit) with light wind, and I went out with them. We had 4 people – a pilot and 3 researchers – in the helicopter. We departed Kaktovik and flew north over the ocean. We saw a lot of tracks but no polar bears until the afternoon. The USGS scientist used a dart gun to inject the polar bear with a drug that immobilizes the animal and puts them under anesthesia. Once the animal was down, we landed, unloaded our gear, and gathered samples from the bear – we weighed it, measured its length, girth, and skull size, and took samples such as fur and blood for later analyses.

One of the polar bears that we captured for sampling on Saturday, on sea ice several dozen miles north of Kaktovik. This is an adult male bear which weighed about 750 lbs.

A front paw of the same adult male. The size of polar bears always amazes me. This bear had paws that were as wide as my hand is long, and it was not even a large male. The largest males can weigh over 1500 lbs, twice as much as this bear. Their claws are shorter and much sharper than a brown bear (also called grizzly bear) – polar bear claws are better for walking on slippery ice and grabbing seals. The long claws of a grizzly are better for different tasks, such as digging up roots for eating.

The fact that the Arctic is so cold is one of the reasons we are studying polar bears – they are superbly adapted to cold temperatures, but how do they fare in the summer, when temperatures can reach over 50 degrees (unbearably warm for a polar bear)? Summer also means lots of sunshine – on the northern coast of Alaska the sun does not set for about 2 months in the middle of summer. Already, in mid-April, days are quite long.

I took this photo of Deadhorse last night at about 1045pm, as the sun was finally setting and twilight remained. The view is from the front door of our lab.

For lab space, we have rented a large trailer from a charter air service company (Bald Mountain). We are also renting several bedrooms in their living space. The setup is convenient for our research – we can wake up next door to our lab, as well as load up our helicopters for captures in front of the lab.

Our lab space is in the white trailer with several doors. Behind is the large hangar that houses the charter air service company.

Past the hangar, the tundra opens up with lots of drifts and sculpted snow.

I have been up here for several days already, unpacking and organizing our bottomless piles of gear. My two advisors and a technician are set to join me shortly, and we will begin our capture work. However, plans are changing. The United States Geological Survey (USGS), with whom we collaborate for capture work, is already in the midst of their capture work based out of a tiny town about 120 miles to the east, called Kaktovik. One of their crew needs to leave several days early and they need me for an extra pair of hands for a couple days. I had already planned to fly to Kaktovik for evening, to participate in a community meeting about polar bear research – I will stay an extra day to help out.

Simultaneously, one of my advisors and the technician will not make it up here on their scheduled flight; a blizzard in the central Rocky Mountains has closed almost all the roads out of Laramie, Wyoming, and flights out of Denver are canceled. The already-rapid pace of preparations has picked up to accommodate these changes.

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.

The “Welcome” sign at the general store in Deadhorse.

Deadhorse sits at the north end of the Dalton Highway, also called “the haul road.” From my understanding, this highway was built as a service road for the Trans-Alaskan Pipeline, which runs from the oilfields of Prudhoe Bay to Valdez where the oil is loaded onto ships. The Dalton Highway parallels the pipeline for much of its long, winding journey. The highway was opened to the public in the 1990s, although it is still mostly gravel and rough driving. The highway begins here in Deadhorse, where I drove past it today on my way to the general store.

North end of the Dalton Highway.

However, we would not be driving to Deadhorse – we have done all of traveling by plane. Alaska Airlines flies to Deadhorse from Anchorage and Fairbanks, and many oil companies have private flights for their workers. The surprising accessibility of Deadhorse – if you are willing to spend days in a capable vehicle or willing to buy an expensive plane ticket – must be due to its role in oil extraction in the Prudhoe Bay oil fields. The town itself feels like a giant construction site. All buildings sit on elevated gravel pads, about eight feet above the tundra. Trucks and heavy machinery are everywhere, and equipment is constantly rumbling.

More accurately, the town feels like a cross between a construction site and a lunar module. Everything is built to withstand the fierce winter weather, with windchills that can fall below -100 Fahrenheit. Most buildings seem to have been built for ease of transport and assembly – many buildings are actually a series of connected, insulated trailers.

Our research team was up here last August for our first season of polar bear captures. We caught almost 30 bears (this includes adults and cubs) for measurements. Some adult bears received a GPS satellite collar as well. We tracked these bears via satellite during September. We returned in October and recaptured as many of these bears as possible, to re-examine them and see how they had changed during the intervening 1-2 months. This spring we are beginning another capture season – our first day of captures, weather permitting, will be Monday, April 20th.