The Great White Bear (10 page)

A few crystals make their appearance on the surface, soon swept together by the wind and the waves and knotting together to create a surface sheen that, as they increase in number, acquires a more oily appearance. This is grease ice, and it is a reliable harbinger of the onset of polar fall, which is itself but a brief layover on the road to winter.

The direction that grease ice takes in following that road varies according to the vagaries of the environment in which it forms. In predominantly calm waters, the grease ice forms long strips of interlacing fingers called nilas ice; in the more turbulent water of the open ocean, the constant movement breaks the continuous ice apart. The resultant fractured pieces are known as pancake ice but to at least one observer more closely resemble lily pads, approximately circular in shape and with raised edges from the grinding of pancake against pancake. The first pancakes are just a few inches in diameter, but as they collide they combine, absorbing each other and growing until they are several feet across.

At this stage, the ice remains sufficiently soft that a ship can push through it with relative ease, although the noise below decks, the grinding and crashing of ice against steel, suggests that greater resistance is being offered. A preponderance of pancakes should, however, be taken as a clue by any wary mariner that the time for departure for warmer climes is fast approaching.

A further slight drop in temperature, a marginal calming of the surface water, and now the pancakes are themselves connected by more grease ice, which itself solidifies further until firm floes begin to form. It is such ice floes that form the basis of the polar bear's realm. Compacted tightly together or separated by open water, it is these that the ice bear patrols in search of its prey.

A floe may be a few yards in size, or it may be as large as several miles. (Larger than five miles in length, an ice floe is commonly referred to as an ice field.) It is never static, either in location—pushed along by currents and the wind—or in size or shape. Over the course of its existence, a floe may break apart, shattered by collisions with other floes or cracking apart through inherent instability and the expansion of once-tiny cracks, time bombs that have sat deep within the floe from the moment of its birth. Or it may grow through the addition of other floes, two or more such masses grinding into each other, becoming intertwined, rising on top of and sliding underneath each other, the whole endeavor causing the floes to thicken and rise up into the air in the form of pressure ridges and to reach down deep into the water below. The scene is one of ongoing movement, a dynamic environment in constant flux.

This is the pack ice: at turns a stable, quiet, desolate, vibrant, crashing, thundering dervish of an environment. The pack constitutes the majority of polar sea ice, but not all of it. In the highest reaches of the Arctic, north of all landmasses, in the polar basin of the Arctic Ocean surrounding the North Pole and extending southward, the "polar pack" is, confusingly, a different beast. Here the ice has become more solid, even more twisted and misshapen; and whereas the ice of, say, Hudson and James bays or the southern Beaufort Sea freezes and melts on annual cycles, the ice of the true Arctic Ocean is just as likely to be several years old.

The reason behind this highlights another distinction between the Arctic and Antarctic. Because Antarctica is a continent surrounded by sea ice, during spring and summer the pack floats unencumbered into more temperate seas as it drifts apart, breaks up, and ultimately melts. But because the Arctic is, in contrast, an ocean surrounded by land, there is but one principal route—the Greenland Sea—via which floes can be transported into the warmer water that will inevitably spell their doom. Because of this, floes in the high latitudes of the Arctic Ocean are more likely to be "multiyear" ice: harder, thicker, and more concentrated than pack made up primarily of "first-year" ice.

But because it is floating freely, it is still pack, even if it is first-year pack's ugly and less frequently encountered uncle. In contrast, fast ice (known alternately as shore-fast, or land-fast, ice), which reaches outward from the shoreline to which it is attached, is spared the constant grinding and collisions of the pack and accordingly is flatter, calmer, seemingly more desolate—"like a lunar landscape," as Brendan Kelly describes it. Because there is less movement and turbulence, there are fewer cracks and openings, fewer opportunities for polar bears to find the prey they seek. And so, when bears head from land to their hunting grounds, they may only pause along the fiat, featureless fast ice, taking advantage of whatever seal-like opportunities they may find en route, tarrying a while if pickings are good and multiple snowdrifts are hiding multiple young seals, before making for the pack.

Sea ice cover in the Arctic is never absolute. There may be large swaths where the surface appears to be nothing but varying shades of white, floes and fields of different shapes, sizes, and thicknesses, first-year blended with multiyear, and the whole twisted and bent into a visual cacophony of chaos. Persist, however, and eventually there will be an opening of sorts to the water beneath—a polynya, perhaps (an isolated patch of water surrounded by ice), a network of leads, a crack here, a hole there, perhaps even a stretch of open water.

When traveling through or across the ice, sea ice cover is measured in tenths as a means of discerning its extent and navigability. Ten tenths means the way ahead is completely full of ice, that there is nary a puddle to break up the solid mass, that forward motion via a seafaring vessel is not an option. Zero tenths means there is barely a chunk of ice to interrupt the journey, that there is nothing but open water in the immediate vicinity.

For polar bears, neither extreme is desirable.

Ten-tenths ice would be of no use to them at all, for although polar bears are creatures of the ice, the species on which they prey are only partially so. For those species, ice is a place of repose, not constant occupation, and one that they are able to reach only when there is access from their primary habitat. That habitat is the water between and beneath the ice floes, and although polar bears are technically marine mammals, in the water itself they are at a disadvantage to the animals on which they prey.

That is why polar bears seem to prefer ice cover that is less than 100, but more than 50, percent: sufficiently broken for them to be able to reach their prey animals, and sufficiently stable for them to be able to do so from the environment in which they have the upper hand. And that is why, for polar bears, unlike almost all temperate and tropical mammals, summer is a challenge and not a time of plenty; as the season advances and the Arctic warms, the ice melts, the cracks widen, and the environment shifts from one of sea ice dotted with fractures to one in which liquid water achieves equivalency and ultimately superiority over the frozen kind. In such a landscape, the location of briefly emergent seals becomes harder to predict before it happens, and more difficult to spot when it does. With seals surrounded by water and with only an increasingly remote and flimsy ice platform from which bears can launch themselves, stealth attacks become all but impossible and most other kinds of attacks unfruitful.

Only once has a polar bear been observed successfully hunting a seal in open water in the summer. In 1978, Don Furnell, a biologist from the Northwest Territories Wildlife Service in Canada, and David Oolooyuk, an Inuk hunter, were watching an adult male polar bear swimming in shallow water about seventy-five meters away from a ringed seal that appeared to be surfacing in approximately the same location each time it took a breath. The bear swam toward the seal's location, then abruptly stopped and lay motionless in the water. When the seal broke the surface a couple of feet away, the bear lunged, biting the seal in the back and killing it. Furnell and Oolooyuk speculated that the seal mistook the motionless bear for a floating piece of ice. Although the two men did note the presence of several seal carcasses along the beach, suggesting more than a few had been caught that way, the behavior has never been observed anywhere else, before or since. Perhaps that one bear deduced a successful method of aquatic seal hunting. But there is no evidence that the practice ever spread or even that that one bear ever repeated its trick.

But while polar bears eat primarily seals, and particularly ringed seals, they do not do so exclusively. They may, for example, either roam along the ice edge or wait motionless for an opportunity to seize a beluga whale. On occasion, belugas have become entrapped en masse in a polynya, unable to escape because the thickness and extent of ice cover in all directions would prevent them from coming up for air. That has sometimes prompted a polar bear feeding frenzy, one or more bears reaching into the water, grabbing a beluga, hauling it onto the ice, and then, before even stopping to eat the carcass of the whale it has just killed, doing the same thing over and over, seemingly unable to resist the primal urge to attack.

In presumably exceptional circumstances, bears will even leap onto the backs of passing belugas. It has not been seen often, but it has been seen: one bear was spotted killing two calves in this way in the space of twenty-four hours. It is a remarkable achievement, requiring the bear to not only make a perfect leap, but also debilitate and kill an entirely aquatic animal in the water.

Bears have even been observed attempting to chase down belugas by swimming after them—but in this they have not been seen to have any success, nor are the odds likely ever to be in favor of their doing so. In fact, researchers have seen belugas lunging at a would-be predatory polar bear and lashing at it with their tails, working as a group to chase it out of the water.

Polar bears, although perfectly competent and at home in an aquatic environment, are simply not credible predators when swimming. Belugas seem to know as much, judging from their apparent lack of fear of swimming bears, and the bears appear to be aware of it, too, particularly in the presence of walruses, which are far and away their most formidable natural foe.

"I've seen bears swimming in the water near walruses, and they're nervous bears," says Brendan Kelly. "They swim as rapidly as they can. In the water, they don't like being near them."

For good reason.

Inasmuch as walruses are known at all, it is, as Natalie Angier wrote in a delightful account of the species in the
New York Times
in 2008, "mostly for their sing-song linkage with a carpenter, an eggman and goo goo goo joob." But walruses are immensely social animals, crowding together on even a relatively small floe until there is barely any room for anybody to move. Males serenade females with a complex and fascinating repertoire of noises that Angier describes as sounding like "a circus, a construction site, a Road Runner cartoon":

They whistle, beep, rasp, strum, bark and knock. They make bell tones, jackhammer drills, train-track clatters and the rubber-band boing! of Wile E. Coyote getting bonked on the head. They mix and match their boings, bells and knocks, they speed up and slow down, they vocalize underwater, in the air, at the bubbly border between. They sing nonstop for days at a time, and their songs can be heard up to 10 miles away. They listen to one another, take tips from one another and change their tune as time and taste require.

The whiskers, or vibrissae, on their muzzle are so sensitive and dexterous that, were one to place a piece of fish on them, a walrus could use them to maneuver that piece of fish toward and into its mouth. A walrus uses those same whiskers to grub around in the benthos, the ecosystem of the sea floor, looking for the clams and other bivalves on which it primarily subsists. Using immensely powerful suction, it is able to vacuum up as many as 7,000 clams a day. But at least some walruses yearn for larger prey.

On one occasion, Brendan Kelly was a part of a team studying whales in Arctic Alaska when a disturbance in the water caught observers' attention.

"The call came that there were two walruses in the water and they were fighting," he says. "They could see tusks, they could see blood flying and wild splashing, and they thought it was a fight between two walruses. So we eventually get out to this little polynya, and sure enough up pops this walrus, and we're crouched behind this little pressure ridge watching this walrus, and it swims around for a little while and then it dives down for about five minutes or so, about as long as you would expect it to take to dive down to the bottom and get some clams, and then he comes up and swims around for a little while. After a while we're thinking there was just one walrus and that the other folks were hallucinating, and then it did something I've never seen a walrus do before. It turns over on its back, like a sea otter, and it's swimming on its back, belly-up, and he takes one of his front flippers, and from under his armpit takes the hind flipper of a bearded seal, puts it between its two front flippers, puts the head of the femur to his lips, and..."

At this point Kelly mimicked the walrus's actions and, by way of illustration of what it was doing, broke the genteel silence in the hotel lobby in which we sat by making a loud sucking sound.

"It was sucking the meat off the bone of this thing," he elucidated. "It's really loud. Then he tucks it back in, swims around, dives back down, comes back up ... he seemed to be alternating between clams and bearded seal. It was wild."

It was all too much for Kelly's dog, which had been straining at the bit to go chasing after this fascinating new animal until, unable to resist any longer, she ran to the edge of the ice. The walrus popped its head straight out of the water, focused its gaze on the interloper, and then sped toward it with apparently malicious intent, until Kelly emerged from behind his hiding place to prevent his canine from becoming another of the walrus dining options for the day.

When polar bears do hunt walruses, they do so from the relative safety of shore or ice floe, and they mostly focus their attention on calves. A Google video search will rapidly enough unearth footage of a polar bear attacking and killing a solitary bull walrus, but success is far from guaranteed. Hans Egede, who in the early eighteenth century was the first missionary to visit Greenland, wrote of walruses that they "are always in battle with the polar bear, and with their huge strong teeth, the walrus can make life hard to the polar bear; yes, the walrus often defeats the polar bear, or in the worst case they make a draw, so that they both end up lying dead at the spot."