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.

An Arctic fox kit.

The foxes seemed as curious of us as we were of them and they posed for our cameras a good fifteen minutes. They used a drainage pipe as refuge, popping in and out until one of them boldly trotted up on the road and sniffed the air in our direction. The other soon followed behind. We heard a strange call, a loud yipping with a high-pitched yowl at the end, sounding every bit the worried mother warning her babies to get out of dodge. The kits paid her no mind, continuing instead to stare at the three of us.

They were the same size and probably from the same litter, but were two different colors. I found out later that Arctic Foxes have two color variants, white and blue, just as Labrador retrievers from the same litter can be yellow or black. The white coat is more common, blues make up about one quarter of the Arctic Fox population. Arctic Foxes molt twice a year, their summer coats are darker and more mottled than the winter coats.

The blue fox.

Arctic Foxes are very well adapted to a cold environment and live almost exclusively north of the Arctic circle. They have a luxurious thick coat and even have fur on the soles of their feet. Their snout, ears, and legs are shorter and more blunted than their more temperate cousins, helping them conserve body heat in winter temperatures that can dip below –58 F (-50 C).

The white fox.

Skilled hunters, Arctic Foxes can usually find abundant prey among the lemmings, hares, birds and fish in their treeless habitat, but they are not above scavenging food from polar bears (taking care to avoid becoming a snack for the bear). The Arctic Fox is circumpolar, found throughout Northern Canada, Russia, Greenland, Alaska, and Svalbard and also in Subarctic Scandinavia and Iceland (where it is that island nation’s only land mammal). In most of its range, the fox is not endangered, except the mainland population of Scandinavia. Here in Greenland they are a common sight in both summer and winter throughout the coastal margins.

We were charmed by the company of these bold fox kits, but it was time to return to KISS for dinner so we hopped back in the truck and the youngsters returned to the shelter of their drain pipe.