Cold (19 page)

Some winter actives store food. The gray squirrel stores nuts. The fox caches eggs and frozen carcasses and biscuits stolen
from Dumpsters. The diminutive half-rabbit, half-hamster, half-pint pika — known variously as the rock rabbit, the whistling
hare, and the coney — dries herbs in the summer sun, making herb hay while the sun shines, then stores it in the caves and
crevices of rock falls. By winter, an individual pika, weighing a third of a pound, may have half a dozen two-pound piles
of herb hay scattered in the rocks.

The snow itself is shelter. The subnivean dwellers — the lemmings and voles and shrews — are winter actives. Their tunnels
in the snow hover right around freezing through the winter. It is not just a matter of insulation. If it grows colder above
their snow tunnels, liquid water in the snowpack freezes, and in so doing releases heat, keeping the temperature in the subnivean
caverns warmer than it might otherwise be. If it grows warmer above the snow, the snow goes from a solid to a liquid, and
in so doing absorbs the heat. The end result is stability, in some ways as important as warmth. For the subniveans, it is
safer under the snow, and through most of the winter, it remains warmer beneath the snow than above, and there is no wind.
If winter behaves well, if the chinook winds are not too severe, if unexpected warming does not ruin the winter season, the
subnivean winter actives know what to expect. But if it grows too warm for too long, tunnels can flood, forcing the subniveans
to the surface, where they face not only the elements but also hungry predators.

The fact is that some of the winter-active animals do more than tolerate the seasonal cold. Some thrive. Lemmings, for example,
are known to mate and reproduce in their subnivean tunnels. They have snowbound orgies and fill their tunnels with young,
thumbing their noses at winter. The young will themselves be old enough to breed and reproduce and raise their own offspring
within weeks of being born. Some will be born and reach adulthood before the spring thaw, when they will see for the first
time the light of the sun and feel for the first time the warmth of a summer day.

And there is food in the snow, food for lemmings and voles and shrews. There is a food web here in these subnivean chambers
that humans seldom suspect. Between the ground and the snow, through the winter, there are fly larvae, beetles, millipedes,
fungi, and bacteria, all of them working over the dead leaves, roots, and branches of the previous summer. Spiders and centipedes
and bigger beetles eat the fly larvae and millipedes and smaller beetles. The shrews and lemmings eat anything big enough
to draw their attention. This is no desert. This is not some cave with only one or two species. In Canada, a scientist poking
around in the subnivean world found nineteen species of spiders, fifteen species of mites, sixty-two species of beetles, sixteen
species of springtails, thirty-two species of ants and wasps, and two species of centipedes, all of them active, living under
winter snow.

And there are seeds. From William Pruitt’s
Wild Harmony: The Cycle of Life in the Northern Forest:

The new snow covered the layer of birch seeds and hid them from the small birds. The added weight of the fresh snow compacted
the middle layers of the
api
[snow cover]. As the crystals squeezed together and broke, the cover creaked and groaned. A foraging vole would stop and
huddle, ears twitching, and then resume its errand. The sounds breached the even tenor of life under the snow. An additional
disturbance was the faint scent of birch carbohydrate that occasionally filtered down from above. Some voles dug upward through
the layers of snow. One layer was easily tunneled, the next was harder; no two were alike. When a vole reached the seed-rich
layer, it drove a horizontal drift along it and devoured every seed.

The tunnels are not without danger. They can freeze over with ice crust, becoming impenetrable. Carbon dioxide can build up.
When warm snaps and chinook winds melt the snow and send floodwater into the tunnels, voles and lemmings and shrews can drown
in their chambers. And if there is not enough snow, if the world grows cold before the snow grows thick, as often happens,
the subniveans freeze to death, or starve trying to stay warm, or, as is closer to the truth, starve and freeze to death and
succumb to disease simultaneously, like Greely’s men and De Long’s men and Bering’s men.

The interactions between animals and their environment do not flow in a single direction. As the first line of a poem affects
the last and the last line affects the first, the environment affects animals and animals affect the environment. Subnivean
winter actives change the nature of the snow, creating caverns for meltwater in spring. Above the snow, foraging hares and
caribou and moose change the nature of their forage. Along rivers, hares eat willows, and on higher ground they eat birch
saplings. This winter feeding can be intense enough to control the structure of the forest, as if the animals are farming
the trees, keeping them small and as succulent as possible year after year. But the plants fight back. Invisibly, the plants
produce compounds that deter winter grazers. The paper birch makes papyriferic acid. In succulent juvenile plants — plants
that appear juicy and tasty — the acid may be twenty-five times more concentrated than in adult trees. At times, it forms
droplets on the winter twigs of saplings. Captive hares, offered birch twigs with naturally high concentrations of papyriferic
acid, stopped eating. There is reason to believe that the coming and going of some hare populations, usually blamed on hungry
lynx, may be a result of chemical defenses in plants. As the hares graze, the plants produce more of the compounds that deter
grazing, becoming less edible, and the hares die back. With fewer hares and less grazing, the plants become more edible, and
the hares grow more abundant.

Winter for hibernators is safe; for bears, as few as one percent might die in their dens. Winter for winter actives is dangerous.
It is not the single cold spell that kills a caribou or a moose, but rather the additive effect of cold spells and snowstorms
and missed meals, or even the effects of one winter adding to the next, with summers too short for the animal to recover fully.
One summer, they are a bit on the slim side, the next summer they have slimmed down a bit more and do not reproduce, and that
winter they die from starvation or disease or, too slow to escape, from a set of teeth ripping through the jugular or crushing
the skull. A pack of wolves can consume a moose every few days. The wolves will also eat caribou, beavers, hares, voles, and
shrews. Shrews are also subject to attacks by weasels and owls. While a shrew hunts bugs under the snow, an owl or a weasel
or a fox hears the commotion and crashes through from above, bringing sudden daylight and death into the tunnels below.

Winter actives must deal with humans, too. Snowmobiles and skiers spook the animals, pushing them into an energy-wasting run.
Fences prevent them from reaching better grazing. Roads make convenient corridors for winter movement, luring animals to death
by unexpected impact. In Wyoming, in 2004, a vehicle ran through a herd of pronghorn, killing 17 animals. In 2006, it happened
again, another vehicle in a different place killing, coincidentally, another 17 animals. Railroads, too, make deadly corridors.
A train heading west through Wyoming one winter ran through a herd of winter-active pronghorn, rendering 125 of them suddenly
and permanently inactive, dead on the tracks.

It is December tenth and thirty-seven degrees in Whittier, Alaska. Six inches of slush cover the parking lot, and rain falls
at a slant, carried by wind. I am wearing a dry suit, a scuba tank, and thirty pounds of lead. Under my dry suit, I wear two
nylon T-shirts, a wool sweater, sweatpants, thick socks, and coveralls made of Thinsulate. Three-finger mitts, a quarter of
an inch thick, cover my hands. The water is thirty-nine degrees, two degrees warmer than the air. A sea otter swims on the
surface, watching me dive. Below, stunted kelp dusted with glacial sediments grows on rocks and gravel. On the seabed, spot
shrimp dart about between rocks. Multiarmed starfish crawl around on their tube feet searching for shellfish. At eighty feet,
I swim through a field of pale sea whips, a cold-water soft coral that grows in vertical ropes rising six feet from the bottom.
The stalks are covered with tiny eight-armed polyps. Nearby, two copper-colored rockfish sit on the bottom, thick finned,
huddled in depressions in the mud, as if trying to stay warm. The kelp, the shrimp, the star-fish, the corals, and the fish
all have enzymes that work reasonably well in thirty-nine-degree water. I do not.

Dry suits always leak. They are not dry suits so much as damp suits, with water sneaking in through the wrist and neck seals.
Moisture leaves my arms and chest clammy. At twenty minutes, my hands are numb. The blood vessels in my fingers, especially
near the skin, have squeezed shut, dropping the blood flow to ten percent of normal, conserving heat for my core. I can still
use my mitted hands to work my dry suit valves, but it is increasingly hard to move individual fingers. My air consumption
increases. At forty minutes, my hypothalamus, buried deep in my brain, somewhere behind my nose, triggers shivering. As a
rule of thumb, shivering starts when the core temperature drops to ninety-seven degrees, two degrees below normal. Muscles
contract and relax in an effort to generate heat, cycling six to twelve times every second, burning glycogen like there is
no tomorrow, generating four times more heat than the body at rest. When the glycogen is gone, the shivering stops. Or if
the body temperature drops to about eighty-eight degrees, the shivering stops, and then, in all likelihood, there is no tomorrow.

I try to think warm thoughts. I repeat the mantra “I am warm. I am warm. I am warm.” In fact, I am not. The mantra fades,
and I think of Laurence Irving’s airman, experimentally exposed to the cold, shivering so violently that Irving worried that
he might shake himself apart. I am abject and miserable, wishing that I had the blood of one of Darwin’s Fuegians. I think
of my caterpillars, Fram and Bedford, lying curled up in my freezer, frozen solid. I envision a ground squirrel in its hibernaculum,
shivering when its body temperature drops below freezing, warming up and then drifting back into the stupor of cold in a cycle
that repeats itself through the winter. And then there is Apsley Cherry-Garrard, writing of the relative warmth of fifty-five
degrees below zero.

The
U.S. Navy Diving Manual
has this to say:

Hypothermia is easily diagnosed. The hypothermic diver loses muscle strength, the ability to concentrate and may become irrational
or confused. The victim may shiver violently, or, with severe hypothermia, shivering may be replaced by muscle rigidity. Profound
hypothermia may so depress the heartbeat and respiration that the victim appears dead. However, a diver should not be considered
dead until the diver has been rewarmed and all resuscitation attempts have proven to be unsuccessful.

For navy literature, these might pass as reassuring words: you are not dead until you are warm and dead.

The manual also warns that regulators can freeze underwater, dumping the diver’s air supply in a steady free flow. And it
says, in one understated sentence, that “hypothermia may predispose the diver to decompression sickness.” At any temperature,
under pressure, nitrogen in the diver’s air supply dissolves in the blood. If the diver surfaces too quickly, the nitrogen
leaves the blood as bubbles, damaging tissue and blocking capillaries. The results can mirror those of a stroke: pain, numbness,
paralysis, loss of memory, dizziness, death. But low temperatures increase the solubility of nitrogen, so the cold diver takes
on nitrogen more quickly. Worse, as the diver grows colder, constricted blood vessels in the hands and feet do not allow the
blood flow needed to flush dissolved nitrogen efficiently. Worse still, it quickly becomes too cold to seriously consider
a slow ascent or a decompression stop. By now, though, I am too cold to focus on any of this. The thoughts just pass through
my mind, as if part of a dream. I am dangerously cold to be underwater. I signal my dive partner that it is time to head up.

I am soft. The ama divers of Japan and Korea would find my softness amusing. For more than a thousand years, they have picked
up seafood, diving on a breath of air. For a brief period, they dove with helmets and canvas suits, but they saw that this
sort of diving would soon exhaust the fishery. Rules emerged that restricted divers to a breath of air. In most places, an
ama can wear nothing warmer than a partial wet suit. The thinking is that only the toughest and most skillful divers should
succeed. They work in water as cold as fifty-seven degrees. At this temperature, softer people are exhausted or unconscious
within two hours, and predicted survival times are less than six hours. The ama often work for three or four hours at a time.
Almost all of them are women. Men, it is said, cannot handle the cold. Some of the ama dive into their seventies. They are
not demure. They have a reputation of independence, of rude language, of loud voices. An anthropologist who once lived and
dove with the ama remarked on their swearing and summed them up by describing their means of greeting one another: they would
say, in Japanese, “Yo!” instead of “Hello.” The ama, she wrote, stay in the water as long as they can, becoming at least mildly
hypothermic on a daily basis. They return to shore and huddle inside their
amagoya
warm-up shed. The anthropologist wrote of returning to the
amagoya
one afternoon. The ama were withdrawn and sullen after an unsuccessful day in the water. It was raining. Everyone was cold.
As they warmed up, they began to laugh and joke. Two of them put on costumes to entertain the others. “You see,” one of them
told the anthropologist, “if we laugh we can forget how damn cold it is!”