By Sanjayan

The polar bears assemble slowly in ones and twos, feigning indifference to us. That's how all bears prepare for attack — with sly and oblique approaches. And polar bears are the undisputed masters of the technique.

I've come to the Arctic on behalf of the Discovery Channel to co-host a documentary, "Expedition Alaska", billed as a “white knuckle ride through the Alaskan wilderness set against the backdrop of climate change.” And I am about to overdose on the “white knuckle” bit.

Polar bears are carnivorous. And because they live in an expansive, largely monochromatic landscape, anything out of the ordinary — our truckload of humans, say — is considered with keen interest.

For a polar bear, if it’s not rock or ice, it’s probably food. And right now, we humans are proving uncomfortably irresistible to the 17 bears loitering outside the truck.

Climate Change = Very Hungry Bears

We've been huddled inside this old two-ton Chevy for hours, waiting for the bears to arrive and feast on a whale carcass we came upon.

And now the Discovery film crew and I are doing our best to disappear by shrinking into the worn seats as the bears — typically solitary animals — circle our truck like ice floes.

We probably look to them like a huddle of fat and stupid seal pups. Polar bears are marine rather than terrestrial mammals — entirely dependent on the sea for food and on the sea ice as a platform for hunting and birthing.

But last spring — with the ice breaking up and retreating swiftly away from the coast — these bears were forced to make long swims to these beaches to search for walrus and to scavenge whale carcasses.

By the time the bears reach land, they are basically starving. And now they're stuck.

On this fall day, the ice is more than 200 miles away, too far to swim.

So the bears must wait until the sea freezes again and allows them to pad back to their usual hunting grounds. That may take many weeks. Ice is now forming in the Arctic Sea later each fall, forcing beach-bound bears to wait and go hungry.

Climate change is causing the changes in the ice pack. And human activity, like flying to Alaska and driving to this place and cranking the Chevy’s heater for warmth — all in the name of conservation — is causing the climate to change.

Some scientists believe the animals eyeing us now may be the last generation of wild polar bears in the United States. That’s the case being made as the federal government weighs whether to list polar bears as endangered based on climate change — a first.

But right now, the bears seem fine. We’re the ones in imminent danger.   

Then…Whomp!

A male, massive in length and bulk, comes over to investigate — sniffing, licking and nibbling at the bumper, the doors, the locks.

Then it rears up on its hind legs — its shaggy, creamy fur blocking out the light — and presses its paws against the windows, which creak ominously.

“Don’t worry,” says Art, our local guide and driver. “The window flexes.” We are silent — perhaps awed, most definitely scared.

Then…whomp! The whole two-ton vehicle lurches, the bear now using the same moves it would when hunting — leaning back and bearing down with both paws held stiffly in front — to crash onto the vehicle.

Art puts the key in the truck's worn ignition — and it slips out, falling on the floor.

He scrambles to find it. When he finally does and tries again, the truck is cold and slow to start. James, our producer and cameraman, has jammed his foot against the rear door, and each blow by the bear reverberates through his knee.

Yet even in the chaos of the moment, as we all scramble away from the windows and Art struggles with the ignition, I sort of know that the evening won’t end in tragedy.

Dangerous as this situation may look and feel, the engine will turn in a few seconds, and we will be on our way.

The polar bears, however, are firmly stuck.

The opinions expressed in "Wild Life" are the author's. They should not be construed as the position of The Nature Conservancy.

Read Other "Wild Life" Columns:

• March 2008:
  The Ghost Bird
• February 2008:
  Worth a Thousand Words
• January 2008:
  The Jaguar and the Tiger
• December 2007:
  I'm the Diversity
• November 2007:
  Should We Save the Last Intact Places?
• October 2007:
  The Encounter
• September 2007:
  Climate Change and the Arctic
• July 2007:
  Mr. President and his Monkeys
• June 2007:
  The Perpetual War for Nature
• May 2007:
  A Road Called Optimism
• April 2007:
  The AIDS Drain on Conservation
• March 2007:
  Blood and Diamonds
• February 2007:
  To Shoot a Lion

Nature picture credits (left to right): Photos © Sanjayan (Polar bear attacking truck in Alaska); © Erika Nortemann/TNC (Sanjayan)