Cold Read online

  And from the world of well-meaning animal conservation: too much warmth in winter kills bats. Indiana bats spend the summer spread out across the eastern United States, but in winter most of them flock to a handful of caves. Half of the world’s Indiana bats overwinter in two caves. In 1967, Indiana bats were protected by law because of continuous population decline. What happened? Cave entrances had been modified to prevent cavers from disturbing the bats. The new entrances — now too small for humans but big enough for bats — restricted airflow. Caves breathe: as the temperature changes outside, air moves in or out of the caves. It is not unusual to feel a strong breeze well underground. When the entrances were modified, the caves became asthmatic. Winter temperatures in the caves rose. At Kentucky’s Hundred Dome Cave, temperatures rose almost twenty degrees. Hibernating Indiana bats maintain a temperature close to that of the air. At lower temperatures, their hibernating metabolism is very slow. They survive the winter by slowly burning through limited fat reserves. When the temperature increases, their metabolic rate increases. Slowly, during their winter sleep, warm Indiana bats starve to death.

  It is August fifteenth. It is around sixty degrees. I sit in the rain outside a yurt thirty miles north of my home in Anchorage, Alaska. A yurt is a round, semipermanent tent modeled after those used by nomadic Mongolians. But this yurt is here in Alaska rather than there in Mongolia, and it is furnished with a woodstove, bunk beds, and folding chairs. Beneath me, I can see and hear the Eagle River, which flows from Eagle Glacier, out of sight some fifteen miles upstream. I look periodically for a grizzly sow and her cub, which were seen by hikers just yesterday feeding on salmon in the river. Now the grizzlies are as invisible as a North Slope caterpillar.

  The Eagle River valley is U shaped, scraped out by a glacier, without the steep-cut angles of valleys cut by flowing water. Higher up in the mountains around us, other valleys end in waterfalls that stream down the sides of mountains. These hanging valleys mark the surface of the old ice, hundreds of feet up. In the past, the big glacier, the thick one, flowed through this valley, extending up beyond what today are the high mountain passes, and the glaciers in the higher mountain passes intercepted the glacier that flowed through this valley. The glaciers in the high mountain passes flowed into the larger valley glaciers like shallow streams flowing into a deep river, leaving their beds perched well above the bottom of the deep river, but these were streams and rivers of ice, moving with leisurely, mountain-grinding power. Boulders carried by the glaciers litter the valley floor. My son climbs the boulders while I stare at the mountains, imagining this place buried under hundreds of feet of ice. This makes me imagine Manhattan under ice. Fifty thousand years ago, the Wisconsin Glacier overran what would become New York. Somewhat famously, it ground grooves into the rocks at Central Park. What would become New York has been overrun by many glaciers, a complicated coming and going of glaciers that advanced and retreated over thousands of years, a cosmopolitan mingling of ice and the effects of ice that make the modern world seem inconsequential. The glaciers in New York are gone now, as is most of the glacier here in the Eagle River valley. All that is left is a pathetic remnant near the head of the valley. The world has warmed. In national parks, there are signposts marking the extent of certain glaciers in 1959, in 1965, in 1970, and so on to the present day. Trees grow around these signs. The glacier itself might not be visible until you are standing next to a sign that says 1959. In ten years, it might not be visible from beyond a sign dated 1970. In twenty years, it might be gone altogether. People say the glaciers in Alaska have retreated. In fact, they have melted, withered, and in some cases disappeared, warmed and thawed into miniatures of their former selves or warmed further until nothing is left but a ghostly memory running over ground rock.

  Tired of the rain, I wander back into the yurt. The park management has left a guest book. Last January, someone wrote, “When we got here yesterday it was three degrees out and not much warmer inside. We got the stove going and got it to seventy inside.”

  Last February, someone wrote, “I hope that the next person that stays in this yurt will have a better experience than we did. P.S. It was minus fourteen Fahrenheit when we got in. We brought my dog with us. Her name is Biscuit.”

  Also in February, someone wrote, “The worst part however had to be the outhouse so cold on the bum.”

  I write nothing. Instead, I stoke the fire in the woodstove. I listen to the rain hitting the tent, audible over the river’s rushing. The next morning, although it is August in a warming climate, there is new snow on the tops of the mountains. It is termination dust, early this year, a dusting of snow marking the end of summer.

  On the prairies, hypothermic and frostbitten children were carried into tiny houses. When times were good, these houses might have been heated with coal or wood. Some families burned dried buffalo bones. Some, when they had to, burned what they called poor man’s coal or prairie coal — little bundles of hay, manually twisted together and fed into a hay burner. The trouble with prairie coal was that it burned quickly and did not put out as much heat as wood or coal or bones. Hay burners had to be fed almost constantly, which meant that someone was almost constantly twisting together handfuls of hay.

  Richard Byrd, in his 1933 solo adventure in Antarctica, would strip off his mask and diving-suit apparel inside his hut in early May — autumn on the southern continent. He wrote of “the small sounds of the hut”: ticking clocks, chattering instruments, and, importantly, the hiss of his oil-burning stove. The stove, unbeknownst to Byrd, was leaking carbon monoxide, slowly poisoning him. It left him weak and confused. “I was at least three hours getting fuel,” he wrote, “heating the engine, sweating it into the shack and out, and completing the other preparations. I moved feebly like a very old man. Once I leaned against the tunnel wall, too far gone to push the engine another inch. You’re mad, I whispered to myself. It would be better to stay in the bunk and cut out paper dolls than keep up this damnable nonsense.” He became despondent. He ignored an overturned chair. He could not bring himself to read his books. He could not get warm, inside or outside. “What baffles me,” he wrote, “is that I have no reserve strength whatever.” Eventually, he radioed his support team. He did not want anyone to know how his condition had deteriorated, so he asked a question, by his own accounting, in “an offhand manner.” His request was simple: “Have Dr. Poulter consult with the Bureau of Standards in Washington and find out: (1) whether the wick lantern gave off less fumes than the pressure lantern; and (2) whether moisture in the kerosene or Stoddard solvent (in consequence of thawing rime in the stovepipe) would be apt to cause carbon monoxide.” A few days later, he had his answer. Yes, carbon monoxide might be a problem. Poulter, however, did not suggest any cures that Byrd had not already tried. On August 11, 1934, near the end of the southern winter, help arrived. Byrd was, by this point, too weak to continue on his own. Without outside help, his heater would have killed him. He would have succumbed to the fumes.

  The human furnace, for a typical adult male, burns through something like seventeen hundred calories a day just to get by. When the body is cold, the burn rate can go up another four hundred calories or so just to stay warm. Shivering can increase heat production four times, but only until the body’s supply of glycogen — a form of sugar stored in the liver and easily converted to the glucose needed by active muscles — is gone. Then shivering stops, and the body temperature plummets.

  At rest, the organs generate most of the body’s heat. The brain by itself accounts for something like one-sixth of the total. In motion, the muscles take over. Moving uphill on skis can burn through more than a thousand calories an hour. Two hours on skis can burn more calories than a full day at rest. Physically fit men, such as polar explorers, can maintain activity levels that burn more than six hundred calories an hour all day long. It is difficult, at this level of activity, to feel satiated. “A pemmican soup,” wrote Frederick Cook of a meal he enjoyed close to the North Pole in 1908, “fl
avored with musk ox tenderloins, steaming with heat — a luxury seldom enjoyed in our camps — next went down with warming, satisfying gulps. This was followed by a few strips of frozen fresh meat, then by a block of pemmican. Later, a few squares of musk ox suet gave the taste of sweets to round up our meal. Last of all, three cups of tea spread the chronic stomach-folds, after which we reveled in the sense of fullness of the best meal of many weeks.”

  Through most of the nineteenth century, the explorers ate pemmican. Pemmican — the real thing, as opposed to the beef jerky marketed as pemmican today — was dried and pulverized meat and bones and berries. Think of something approximating perhaps dried Spam with berries. The meat and bones often came from moose or bison or elk. It tasted as good as it sounds. George Tyson, afloat on ice in 1873 with Eskimo hunters and their wives, described a meal: “We pound the bread fine, then take brackish ice, or saltwater ice, and melt it in a tin pemmican can over the lamp; then put in the pounded bread and pemmican, and, when all is warm, call it ‘tea,’ and drink it. It reminds me very much of greasy dish-water.”

  When possible, explorers supplemented their diets with fresh game, in part for the sheer pleasure of fresh food and in part because of the knowledge that it kept scurvy at bay. There might be seal meat or caribou or fox. Polar bear was not an unusual meal. Many men ate their meat frozen, a habit they learned from the Eskimos. It was noted more than once that food could be cooked with fire or with ice. Father Henry, living in his ice cellar in Canada’s Northwest Territories, subsisted on frozen fish. “For six years,” wrote a journalist who knew Father Henry,

  he had been living on nothing but frozen fish, and he was none the worse off for it. When he awoke he groped on the ground, picked up a great chunk of fish frozen so hard that he had to thaw it out a little with his lips and breath before he could bite into it, and with this he regaled himself…. Boiled rice warmed you while you ate it, but its warmth died out of you almost as soon as it was eaten. Frozen fish worked the other way: you did not feel its radiation immediately; but twenty minutes later it began to warm you and it kept you warm for hours.

  All of the warm-blooded animals need food to stay warm. Some animals conserve calories by hibernating at cooler than normal body temperatures, but others do not. Polar bears, other than pregnant females, hunt seals through the year. Arctic foxes roam the sea ice in winter. Beneath the snow, subnivean life churns on. Lemmings, the size of gerbils, dash through tunnels of hoarfrost at the bottom of the snowpack. Smaller animals lose heat more quickly than larger animals. For their size, smaller animals have more exposed skin — more surface area to cool off for every ounce of fat, muscle, and brain tissue. For their size, they need to burn more calories than larger animals, yet they are not big enough to store much fat. In colder climates, a small animal that cannot store fat cannot hibernate. The smallest hibernator in the far north is the ground squirrel, several times larger than the lemming. And so lemmings eat through the winter. They gnaw on twigs and branches under the snow. Occasionally, when times are hard, they eat each other.

  Farther south, in the American suburbs and frosty cornfields and icy parks, birds foolish enough to stick around through the winter eat to stay warm. It would not be entirely wrong to say that they feed desperately. Golden-crowned kinglets, birds not much larger than a grown man’s thumb, overwinter in places such as Vermont and Maine. Despite thick feathers, they lose heat quickly. Winter ecologist Bernd Heinrich, curious about what they ate, killed a few one winter. “I shot the first kinglet at dusk when the bird’s stomach would presumably be full,” he later wrote. He “took its body temperature as soon as it hit the ground.” The little winged furnace was thermoregulating at 111 degrees. Its stomach was full of tiny caterpillars, previously thought to overwinter as pupae. “To find out how quickly a fully feathered kinglet loses body heat,” Heinrich wrote, “I experimentally heated a dead kinglet and then measured its cooling rate.” At thirty below, the tiny dead bird lost more than five degrees every minute. Alive, at this temperature, the bird would have had to forage almost nonstop. Heinrich followed four of the birds around on a January night. With windchill, the temperature was fourteen below. “The birds foraged tirelessly, without pause,” he wrote. “I timed them at an average of 45 hop-flights per minute, without any apparent change of pace.”

  Cold, really, is like malaria. If it does not kill you, it will help you lose weight.

  It is August twenty-first and fifty degrees. I am wandering along the length of Point Brower, just east of the Prudhoe Bay oil field, with two botanists, a father-son team. We step on diminutive willows and dryas and saxifrage. We splash through puddles full of cotton grass. We peer into shallow freshwater pools full of tiny copepods. There are also crustaceans called tadpole shrimp — not shrimp at all, but from a group called branchiopods, distant cousins of water fleas and closer cousins of brine shrimp, including the ones marketed as sea monkeys. Soon all of these plants, all of these puddles, and all of these little pools will freeze solid. Everything in them will turn to ice. All of this life will be suspended.

  I ask my comrades to watch for caterpillars. Though skunked so far, I have not given up. A lemming scurries across the ground in front of me like a tiny furry pig on espresso. It dashes along miniature pig trails between clumps of plants and through tunnels under the leaves. Neither tunnels nor trails are more than two inches wide. Soon enough, the trails and tunnels will be buried under snow. The lemmings will grow their winter digging claws. They will go about their business under the snow, in their icy white grottoes, chewing on frozen willow stems. The snow will protect them from the bitter cold and wind of the surface.

  At the end of Point Brower, which juts out into the Beaufort Sea east of Prudhoe Bay, sit the remains of three human homes. They were sod huts more than homes, little rectangular boxes ten feet on a side, before their roofs collapsed. The oldest of them, possibly built more than two centuries ago, when Russia ran Alaska as a frontier province, is now nothing more than a low mound of sod. The second oldest has been used as a trash heap and is full of rusted cans and broken glass. The youngest — the remains of a roof still in place, its sod walls full of lemming tunnels and littered with piles of their droppings — could be marketed as an Arctic fixer-upper, beachfront, ocean views, with kerosene tins and rusting cans that suggest it was used as recently as fifty years ago.

  This is treeless country. Structural members in sod homes like these might be bones from bowhead whales or stout driftwood tree trunks. It is Canadian driftwood, carried down the Mackenzie River in Canada to float along the Beaufort Sea before washing up on these gravel beaches, a drift of more than two hundred miles. There are, too, scattered boulders on these beaches, carried here on Pleistocene ice sheets. The sod homes, in modern times, were heated by bottled natural gas or kerosene, and before that by drift-wood and seal oil. In some areas, the locals once burned dried tundra sod soaked in natural oil seeps, where crude oil finds its way to the surface from underlying deposits. The place, for all its wildness, has a feeling of history unusual to find in Alaska, a feeling that the people who came before left a mark, that what might look at first like an untamed coast has been home to people for generations, and that these people traded with other people, and built homes and fostered dreams and ambitions of their own through long, cold winter nights and breezy sunny summer days on the shore of an icy sea that to them did not seem at all untamed.

  One of the botanists asks me about a bird. “It’s a long-billed dowitcher,” I tell him. Soon it will fly off to overwinter in California or Mexico or as far east as Louisiana or Florida, like some of the Prudhoe Bay oil field workers. This time of year, when the plants are still green, the Arctic seems unnaturally quiet. Over the past few weeks, most of the birds have left. There are some stragglers, though, like the dowitcher. The geese and the larger ducks have not yet left. And tiny Lapland longspurs still flit around happily. One, foraging on the ground near me, almost walks over my boot. Soon they will head sou
th to overwinter in suburban parking lots and subdivisions, happily taking handouts from bird feeders through the winter.

  The same botanist who asked about the bird finds what has eluded me — a caterpillar, and then, almost immediately, another. The caterpillars are mostly deep brown, the color of chocolate, but with black trim. Light gray hairs cover their bodies. The hairs look like bristles, but they are surprisingly soft. The hairs slow down airflow, trapping warmth and moisture in a boundary layer around the beast’s body. I let the caterpillars crawl around on my hand. They will make wonderful pets. I will store them in the freezer while I travel. And, if this does not work out, I suppose I can eat them, as Greely’s men did. I name one of them Fram, after the boat that Fridtjof Nansen intentionally froze into the ice. I name the other one Bedford, after James Bedford, the retired psychology professor who, immediately after his death from kidney cancer, had his body immersed in liquid nitrogen. Bedford — the person, not the caterpillar — remains frozen in a facility in sunny Arizona. Although I cannot actually tell Fram the caterpillar from Bedford the caterpillar, neither can anyone else. I empty my lunch bag into my knapsack, throw a few willow sprigs in the empty bag, and then bag the caterpillars themselves.

  SEPTEMBER

  It is September fifth. On the North Slope, the temperature is thirty-nine degrees above zero. On the North Pole, it is just below freezing and overcast. On the South Pole, it is sixty-five below. In Vostok, sitting at 11,484 feet of elevation in Antarctica’s Russian sector, the thermometer reads ninety-seven below. I am in none of these places. Here, in Windsor, England, it is seventy-three degrees and too hot to stand in the sun. I stand instead in the shadow of Windsor Castle. Rumor has it that the queen is present. Security is openly active. My request for an interview has been flatly refused.