Thursday, October 18, 2007

Edged off the Earth

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On a beach along the Hudson Bay, I once snuck up too close to a polar bear and only realized my danger when she rose to her feet and looked at me, 30 feet away.  Polar bears are the largest land carnivore, weighing three times more than the average lion.  If she charged me, there was little chance I'd make it to my truck.  An animal like this could run down a galloping horse.

For several years before this trip I'd been writing a novel about polar bears and the research had culminating in my taking a trip up to the arctic to stand here openmouthed, facing a carnivore who on four feet stood almost as tall as I did on two.  From my research, I knew during the summer and fall, there wasn't enough sea ice for the bears to walk cross the ocean to get to the ringed seals they eat.  With a creature as large as these bears, there aren't a lot of other animals around that could satisfy their hunger.  During the ice-free months, the bears lost on average a third of their weight.  At this moment, it was October and the animal standing in front of me was bony with starvation. 

The reason I'd felt safe enough to sneak in this close was because she'd seemed to be so intent chewing on the body of a husky that she'd dug out of the ground.  From how flat and desiccated the dog's remains were -it looked a lot like a rather stiff bath mat-- it seemed clear the body had been buried for quite a while.  Unfortunately, I'd seriously misjudged the amount of time the husky would keep her occupied.

How can I describe this moment while she considered killing me?  Unlike a shark (that swimming dinosaur), her reactions weren't hardwired.  Looking into her dark eyes was more like returning the gaze of a gorilla or leopard, a creature with surprises.  She watched me, mulling over the pros and cons.

Polar bears live on the edge, the edge of the world and the edge of their ability to survive even during good times.  Spurred on by their harsh environment, they've evolved faster than almost any other mammal, diverging off from brown bears only 300,000 years ago.  In this short time, they've perfected their arctic selves, becoming so well insulated that one of their main problems during the summer is staying cool.  If you put on infrared goggles so your vision was all about heat loss, when you looked at a person, you'd see a fuzzy psychedelic silhouette of heat radiating out into the air (we furless humans are such immoderate folk).  Now turn to look at a polar bear instead.  The animal is utterly invisible except its nose, eyes and the slightly warm footprints it leaves behind. 

The bears are such superb swimmers and spend so much of their lives out on the ice, scientists classify them as marine mammals, similar to dolphins or seals.  They are capable of paddling more than 60 miles without stopping through the freezing ocean.  Their paws the size of dinner plates paddle onward, their dark eyes scanning the water for an ice floe on which to rest.

They also have a canny intelligence.  Churchill, Manitoba is the polar bear capital of the world, where the sea ice across the Hudson Bay forms the earliest because of an unusual confluence of fresh and saline waters.  The bears wait there in increasing numbers in the fall for the ice to thicken enough that they can stride off toward the seals.  Meanwhile, bony with hunger, they nap in garages or stand outside bakeries sampling the air.  Some of the worst encounters between humans and bears used to occur by the Churchill garbage dump, where a person climbing out of their car with their rustling garbage bags might find a polar bear stepping out from behind that old fridge.  In spite of their size and speed, the bears didn't have rifles and so they were the ones who frequently suffered from the interaction.  Decades ago Greenpeace helped shut the dump down, having the townspeople triple-bag their garbage and then incinerate it.  Still, the bears continued to visit the location of the old dump for three full generations.  The mothers taught their babies there'd been food there and even though those babies never found anything there themselves, in this low-caloric world they taught their own children to check out the possibility. 

Within three generations is also how soon the bears will be gone. The ice on the arctic sea has thinned more than 40% in the last five decades.  By 2100, because of global warming, scientists predict not enough ocean ice will remain for the bears to get to the seals to hunt them.  And even this prediction is fairly optimistic. Given the way the arctic is melting so much faster than expected, the bears will probably starve to death a lot sooner.  Greenland's ice melt alone has doubled in just the last five years. The ice floes on the open water are getting smaller and less frequent.  Already, a winter survey of the bear population performed by the U.S. Minerals Management Service discovered the drowned bodies of bears bobbing in the sea.  This was winter, in the arctic.  Still the melting ice floes had drifted so far apart the bears couldn't find one to rest on, not even after 60 miles. 

These same surveys have shown, in the last 15 years, the winter population of bears has shifted from hardly ever being on the land, to being there almost 70% of that time.  With the ice thinning, the animals are wandering far a field in desperate search of some new food source.

If you want to get a sense of how much polar bears live on the margins of the possible --at the very edges of where that big a carnivore can feed itself-- look at their pregnancies.  The pregnancies last eight months and after that the mother dens herself up with the tiny pups for four to six months before she can hunt again.  In order to decrease the risk that both the mother and cubs starve to death in their den or that they emerge too weak to hunt, the fetuses don't implant in the uterine lining until halfway through the pregnancy.  This way, if the pregnant bear can't manage to store enough fat to support herself and her cubs for half a year, she can simply spontaneously abort in hopes of better hunting next winter. 

According to NASA, over the last 25 years, the average polar bear weight has decreased by 143 pounds.  We are edging them bit by bit out of existence.  Long before the last bear has starved to death or drowned out on the ice, there will simply be no new bears born for too many years in a row, all the bears moving past their fertility, all of the cubs aborted in hopes of a better hunting year some time in the future. 

The bear staring at me, that day on the Hudson Bay, was starving and desperate.  Still, she sighed and turned away from me, letting me back away to my truck. 

Humans are not being half so kind to the bears.

(Note: The novel I wrote was "The Cage. " Published in 1994, it predicted the end of the polar bears from climate disruption.

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