The Polar Bear is sometimes referred to as the Ice Bear for a reason: its very existence depends upon the ice, for it is here that the bear finds most of its food. Ice in many areas is transitory, and only in the far north does pack ice remain year-round.
Some of the most productive hunting grounds for Polar Bears occur on the ice that forms through the winter along the shoreline and edges of glaciers and remains locked in place until the summer melt. This fast ice is often pocketed by the breathing and escape holes of Ringed Seals, and this is where Polar Bears will sit or lie in wait for hours, hoping that an unwary seal will surface for a breath.
Alarmingly, climate change is occurring most rapidly in the Arctic regions, as one event or reaction triggers another and reinforces the first, thus compounding the problem. For example, as the area of ice retreats further and further each year, more areas of dark, open water are exposed, and dark water absorbs sunlight, and thus heats up, rather than reflecting back into space. This melts more ice, opening up the seas and, if storms arise, generating bigger waves that in turn break up the pack ice even further. And so the cycle continues, reinforcing the effect and intensifying each year.
If sufficient food was available on land, Polar Bears would not be as dependent upon ice, just as the Polar Bear’s ancestor, the Brown or Grizzly Bear, is not dependent upon ice today. But for the Polar Bear, it is here, in the ice, that the seals that comprise most of the bear’s diet are found, and for this carnivorous bear, the ice is the key to survival.
CONSTANT WANDERINGS
Fresh tracks in soft ice mark the passage of a Polar Bear. Sometimes the trail meanders in a seemingly random manner, though it is likely that the bear is investigating new scents. Tracks in a straight line might indicate a male that had scented either a female or a fresh kill that the bear will try to scavenge.
CONSTANT TRAVEL
Photo: Hugh Rose/hughrosephotography.com
Polar Bears travel constantly, and the average bear may cover the equivalent of a coast-to-coast trip across the United States in a single year. Bears may travel ten to twenty miles a day, but some bears may double that distance when necessary.
HUNTING THE EDGE
A Polar Bear follows the edge of the fast ice, perhaps heading toward an unbroken expanse of ice where Ringed Seals will maintain breathing holes. If necessary, bears will swim toward new locations, but they are more likely to remain dry if they can.
A LEAD
While the Arctic seas may appear calm, tidal forces, currents, and wind are constantly at play, and sometimes the stress cracks and spreads the ice. These openings, called leads, may extend for miles, before the ice slides together again, often forming pressure ridges that resemble miniature mountains. This movement of the ice inspired the concept of continental drift, a theory once discounted but now universally accepted as an explanation for much of the planet’s landforms.
A DAUNTING MAZE
Photo: Adam Rheborg
Polar Bears prefer platforms of solid ice, and head either to land or to pack ice once the ice cover drops to less than 50 percent of the total area. For this bear, any travel will involve a lot of swimming until the bear reaches a more stable platform. As the Arctic warms, more and more ice platforms shrink, making travel for the bear increasingly difficult.
TRAILING ALONG
Photo: Adam Rheborg
A mother Polar Bear leads her two cubs across the fast ice that formed along a glacier’s face. This is prime Ringed Seal habitat, and this family may remain in the general area, hunting seals, until spring arrives and the fast ice melts.
THE GLACIER FACE
Photo: Adam Rheborg
A Polar Bear pauses on a small iceberg, calved from the towering glacier nearby. Glaciers, like this one in Svalbard, are retreating so rapidly that the shallow water nearby may be relatively unproductive, as the sea bottom has not yet responded to the change. With time, the now-exposed sea floor will support a variety of life.
A SPECTACULAR LOOKOUT
Photo: Adam Rheborg
Rising high above the surrounding sea and often steeply walled, icebergs are not productive hunting areas for Polar Bears. Some icebergs are blue, an indication of old ice where gases have been forced from the ice over time. Analysis of the remaining air trapped within an iceberg or a glacier provide clues to the Earth’s past climates.
PATIENTLY WAITING
Although this Polar Bear appears to be sleeping, it is actually on the alert. Should a seal surface for a breath of air, the bear will respond instantly, attempting to catch its prey before the seal can escape beneath the ice. Bears typically remain an hour or so at a breathing hole, motionless, as any movement might be detected by an approaching seal.
TOO MANY CHOICES
Photo: Adam Rheborg
As ice begins to melt, Ringed Seals may surface anywhere. For a Polar Bear, a hunt becomes a game of chance. Ringed Seals may use the same breathing hole or lead several times, but will eventually move on to another, lessening the chance of it being ambushed. Eventually, there will be too many holes to choose from, and the bear must move on, either returning to land or moving off onto the pack ice.
“. . . FOR THE BEARS, HUNTING BECAME EASIER, AS SEALS WOULD BE UNABLE TO SPOT A DISTANT, STALKING BEAR.”
IN THE FOG
As warm air passed over melting fast ice, a thick fog developed. From our ship, spotting distant Polar Bears became an almost impossible task, but for the bears, hunting became easier, as seals would be unable to spot a distant, stalking bear.
THE CHARGE
Polar Bears travel at a steady pace of about two-and-a-half miles an hour, which they can maintain for days. Their powerful build is not designed for speed, but in a charge after a stalk that takes the bear within 100 yards of a seal, Polar Bears can reach twenty-five miles per hour, as it races to catch a seal before it can slip into the water and safety.
BLOODY FUR
Photo: Tom Wester
Swaths of blood soil the immaculate fur of a Polar Bear, evidence of a fresh kill. In spring, when Ringed Seals are giving birth and nursing young, and through the first weeks of summer, when weaned young seals are still naïve and vulnerable, Polar Bears may make a kill every three to five days. This is their time of bounty, as they put on the layer of fat they’ll need to survive during the ice-free months.
STILL HUNTING
Perhaps the lingering scent of a seal has prompted this Polar Bear to hunt along this ice edge. Polar Bears may lie still like this for hours, patiently waiting for a seal to surface for a breath. The energy expended by hunting in this way is minimal, but success is still a matter of some luck.
CATCHING THE SCENT
It is fairly certain that Polar Bears can detect prey or fresh kills from about one mile away. When a seal is seen, or smelled, the bear begins its stalk. Hunting in this way is less productive than still hunting (more on this on page 60), where a bear waits at a breathing hole—but watching a hunt transpire in this manner is certainly exciting!
