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November/December 1999 issue	In this issue Table of Contents Editor’s Notebook Inside Story Feature: Cape Breton coal Whale-eating bears

Two polar bears belly it up to feast at a breathing hole kept open by whales trapped under sea ice for about 60 days last spring in Lancaster Sound.

He was reminded of this fact again last May, on what was supposed to have been a routine research trip over Lancaster Sound, off the north coast of Baffin Island. The plan was straight-forward. With the help of a helicopter pilot and colleague Susan Polischuk, Ramsay would fly out over the sea ice, as he had done hundreds of times before, to look for polar bear tracks. Since the animals regularly come this way to hunt for seals, this would not be as difficult as one might suppose: the prints stand out, crisp and clear, in the polished snow. By locating one of these dotted lines and following it to its source, the researchers had an excellent chance of tracking down a bear, which could then be tranquilized with a dart shot from the air. Once the animal had been immobilized, the team would land and collect a set of measurements — weight, age, sex, reproductive status, and more — to add to their store of baseline data.

At first, everything went as expected. After a couple hours of searching, they came across a braided skein of tracks and, half an hour later, the cry went up that a female and two yearlings had come into sight. But then something odd happened. As Ramsay was busy preparing the tranquilizers, Polischuk shouted out that she had seen another bear. "And another. And another. And look, over there!"

As her excited voice tallied more and more sightings, Ramsay listened in disbelief. Apart from mating season (which was over for the year), adult polar bears do not hunt or travel together on the sea ice. So why had all these individuals — more than 20 — suddenly chosen to gather here, on a stretch of frozen ocean?

Imprisoned by the ice and gouged by bears, a pod of belugas come up for air.

Sassat is a Greenlandic word for a group of animals caught in the ice. In this case, the victims were whales — more than 40 belugas and at least one bowhead — which presumably had swum west from Baffin Bay during a warm spell in early spring and become entrapped when conditions changed. Now, they were keeping their breathing holes open as they surged to the surface for air. Until the ice broke up, they would be prisoners in this spot, unable to stray from their oxygen source.

Meanwhile, the trapped whales attracted the bears, which may have detected them through their super-keen sense of smell. The bears backed away when the helicopter set down near one of the ponds, but signs of their depredations were everywhere. Many of the whales in the water had been bitten and clawed, and eight dead belugas were sprawled along the margins of the ponds where, apparently, they had been dragged by the bears. (How does a quarter-tonne bear lift a tonne of dead weight? "Polar bears are very strong" is the best that Ramsay can say.) After stripping the blubber from the carcasses, the bears had ceded the rest to the thousands of glaucous and ivory gulls wheeling overhead.

Researcher Susan Polischuk is dwarfed by the intimidating bulk of a male polar bear, tranquilized after feeding at the sassat. He weighed in at 471 kilograms.

Yet Ramsay believes that sassats and other similarly random events may be of critical significance to polar bears and other Arctic marine mammals. Sea ice is terra infirma, as restless as wind and waves, a realm of slow, relentless, capricious change. In this fluid medium, the geography of life and death can be radically redrawn within days or weeks. (The sassat, for example, was gone without a trace when the site was overflown again about a month later.) "If scientists aren’t there to witness these key events," Ramsay says, "we are missing what’s important."

As evidence, he points to his data from the sassat. The four bears he weighed and measured at the site were rippling with fat. At weights of about 300 kilograms for females and almost 500 for males, these animals were each about 150 kilograms above the average for late May. In fact, they were so gloriously obese that Ramsay predicts they may not have to eat again for another year.

 Impossible? For a mere human, yes. But, as Ramsay’s research has shown, polar bears are superbly adapted to life in the High Arctic, where food supplies are as vagrant as the sea ice itself. When resources are abundant, their bodies balloon with fat; when prey is scarce, they draw calories from this bank. Unlike most other mammals, which need a constant supply of protein, polar bears can go for months on virtually no food at all.

 Ramsay and his colleagues have recently discovered that they do this by switching from a "normal" metabolism into a special "fasting" state, the same mode that other bears enter when they hibernate. In this condition, a polar bear often remains active, yet can go without food for four months, eight months, perhaps even a year, provided it has sufficient fat reserves. A bear that has gorged at a sassat will not have to prey on seals, which in turn will survive to eat more fish, and the perturbations will echo on through the food chain.

Viewed from this perspective, a sassat becomes much more than a spectacular, short-term event. "I believe that we have been privileged to catch a glimpse of something truly significant," Ramsay says, perhaps even one of the keys to understanding the unexpected intricacies of life in the High Arctic.

Candace Savage is a Saskatoon-based writer and author of 18 books on wildlife, environmental issues and other subjects.

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