The World of the Polar Bear

Excerpted from Chapter 1:
The Polar Bear's Den

The countryside whizzed past beneath us in a green-and-white patchwork stitched together from the alternating fabrics of conifers and snow. Heading south, we crossed the tree line and followed the route of a meandering creek, where we noticed large snowdrifts deposited on the lee side, an ideal location for polar bear dens. When the helicopter pilot suddenly spied bear tracks directly below, he executed a steep descending turn that gave me a momentary flashback to my morning meal.

Flying close to the tops of the highest trees near the creek, we were able to follow the tracks. "There she is," I heard Dennis Andriashek, a Canadian Wildlife Service scientist, shout through the earphones. "She's sticking her head out of the den. And look! There's a young one." As we banked to the right I was struck at once by how elusive these maternal groups are, even in the most heavily populated denning habitat in the country.

In recent years I have searched for polar bear families with the help of Morris and Mike Spence, and their friend Ellen (Amak) Oman. The Spence brothers not only own the famous Wat'chee Lodge, located on the edge of Wapusk National Park, but they also serve as guides to tourists, photographers and film teams visiting the area. It's not an easy task to find the dens, given how well camouflaged they are and the size of the park. I once asked Morris what his secret was.

"There is no secret," he replied. "This is all tribal land. Everything I learned out there I learned from my father, other family members and friends. I can read the clouds for weather changes, the color of the ice, the snowdrifts. I travel with open eyes and an open mind and try to put myself in a polar bear mother's position searching for shelter."

In anticipation of the arrival of their offspring, the Wapusk females bears dig earth dens or move into existing ones used over the years by many generations. Females in other denning areas search for a suitable snowdrift in which to excavate a comfortable chamber. They usually dig out a single room averaging 6 by 10 feet (2 by 3 meters) in area and 4 feet (1.2 meters) high, but two- and even three-room dens are not uncommon. The den's roof is thin enough to allow oxygen to pass through the snow crystals - so thin, in fact, that a fellow photographer once strolled over a slope and broke through one. Fortunately, his leg plunged into an unoccupied spare room!

In her igloovikus, as the Inuit call it, the bear drifts in and out of sleep, living off her fat stores from the previous winter's hunting and waiting to give birth. The young are born sometime between November and February. Twins and, less frequently, triplets make up the typical polar bear family; only one litter of four has ever been documented.

At birth, the polar bear cub is smaller than a tree squirrel, weighing less than two 2 pounds (1 kilogram). With only a light down covering and its eyes still sealed shut, the newborn is completely helpless. In this undeveloped condition the cubs are vulnerable to the cold. Scientists have found that the mother's body heat coupled with the insulating layers of snow covering the den can keep the inside temperatures only a few degrees below freezing, regardless of how frigid the outside temperatures become. During their first three weeks of life, the cubs curl up on their mother's thighs for protection from the frozen ground.