The Ragged Edge of the World (22 page)

Perhaps the use of weapons grew out of threat behavior, but there are many other possibilities. Carole wonders whether Imoso might have gotten the idea from seeing farmers who have invaded the park brandish sticks and machetes at the chimps when they stage crop raids. Wrangham doubts this, but whatever the origins, Uganda is a fitting locale for the first observation of a primate using a weapon against one of its own.

But this was not to be the last word on chimpanzees using weapons. Six years later, in 2007, Jill Preust of Iowa State University announced her findings that savannah chimps in Senegal fashion sticks into spears, which they use to hunt small primates called bush babies. We are likely to learn more about chimps and weapons, as one of the noteworthy takeaways of chimp research over the past four decades is that observers continue to find evidence of new behaviors in well-studied populations of animals.

“New” in this case means new to science, and not necessarily to chimp behavior in general. For instance, since the 1980s Swiss scientist Christophe Boesch has been observing chimps using granite stones to crack panda nuts in the Tai Forest in the Ivory Coast. (The chimps place the nuts on flat wood or a rock and then use the stone to break open the nut.) When I went to visit Christophe there in 1990, no one knew how long chimps had been using these stone tools. Then, in 2007, Julio Mercader of the University of Calgary uncovered ancient nut-cracking stones in Tai that dated back 4,300 years—even before early Africans started using agriculture in that region. The discovery underscores the point that chimps could do something in proximity to humans for thousands of years before the behavior was first discovered by science.

The other lesson of these discoveries is that “new to science” also does not mean new to the Pygmies who have lived in the forests for thousands of years as well. Testimony of Pygmies about chimp and gorilla behavior has often turned out to be a long-leading indicator of what scientists eventually see for themselves. That productive synergy will last only as long as Pygmies continue to go into the forests, there are forests for them to go in to, and there are apes in the forests to be seen.

But all that may not be the case for much longer. A few years after I visited the Tai Forest, an Ebola epidemic decimated the colony I had observed, wiping out twenty-five chimps in a population that numbered just a few score. A few more such outbreaks or a poaching massacre, and there might not be chimps to pass on the knowledge of how to use stones to crack panda nuts. Whatever forest peoples visited the Tai Forest vanished long ago, and the forest itself has only a fragile purchase in an increasingly desiccated (in the time Christophe has been studying the Tai Forest, it has already lost one of its two rainy seasons) and deforested surrounding landscape.

The Central African rainforests, where Teti the Ba'Aka Pygmy claimed to have witnessed chimps battling gorillas, have a better chance of persisting, but there are no guarantees that if they do, they will be populated with chimps and gorillas, or that Pygmies will maintain their unsurpassed knowledge of the terrain and its animals. I have no idea whether Teti was being honest about his accounts or simply pulling my leg, trying to see how far he could go in spinning tales for gullible visitors. His tale certainly strains credulity, but so did the now-confirmed assertion that chimps use sticks as weapons.

If these interspecies battles are confirmed sometime in the future, it will be very good news—not because it will mean that another species besides humans uses weapons in organized warfare, but because it will mean that there will be chimps and gorillas still living their lives in their natural habitats.

H
umans cannot really live in Antarctica except for a few brief months during its summer, and then only with precautions similar to those one might take in preparing to live on the moon. That said, humanity is having a profound impact on the vast continent. Thanks to our meddling with the chemistry of the atmosphere, we have pulled off a necromancer's trick: We have unfrozen time.

On the great ice sheets at the southern end of the earth, the far past and the present meet daily. The past rises from the depths of the sheets in the form of temperature changes in the ice that are ghosts of climates long past. In other parts of Antarctica, time doesn't stop, but rather walks in place. Antarctica is an illusionist itself, and its conundrums are but one aspect of the continent's personality. It also presents a face of haphazard ferocity, where nature is in charge. The ocean surrounding Antarctica is the stormiest on earth; its storms are the strongest. Antarctica is earth's highest continent, with an average elevation of roughly 7,000 feet, but also the lowest, since the actual land surface is about 1,600 feet below sea level. The enormous weight of two miles of ice compresses the very crust of the earth. In some places Antarctica's beauty derives from its immense scale and extremes, in others from its purity, and in others from its colors.

Antarctica is an alien icebox, isolated from the habitable world by ramparts of ocean and air currents. Those who make the trek to this antipode venture into a redoubt where the normal rules don't seem to apply. In fact, much of the strangeness one encounters there results from the simplicity with which the workings of geophysics play out in the slow-motion world of extreme cold without the interference of biology. The consequences can be magical. Scientists report seeing icebergs and islands hovering upside down on the horizon. Through the mechanics of physics, Antarctica can confer on a dead seal the splendor of Arthurian burial rites.

Let's say, for instance, that a seal dies in shallow waters. The corpse will quickly freeze to the bottom of the ice at low tide, and rise slowly to the top as ice forms below it and evaporates above. Once it has made its way to the surface, the seal's body rises onto a pedestal as it insulates the underlying ice from the sun. Eventually the ice breaks up, and the seal, now mummified by the sun and dry air, drifts out to sea. If cold air is flowing down from the ice sheets, the refraction of the sun's rays will create a mirage and it will appear as if the seal is standing as it sails off toward its icy Avalon.

In other parts of Antarctica, dead seals experience perpetual resurrection as a result of the interplay of sun and ice in an environment that never changes. For instance, a short helicopter ride from McMurdo, the main American base on the continent, lie the Dry Valleys, so named because they are free of ice. Scattered through these valleys are frozen lakes fed by runoff from the scores of glaciers that hover at the edges of the valleys. Seals occasionally wander into these valleys but quickly die of the cold (the average annual temperature is 20 below Celsius) or starve—the valleys are so devoid of any form of life that a surgeon could operate on a patient lying on its soil without fear of introducing an infection.

Some of these ill-fated seals end up on the ice on top of Lake Hoare, deposited there by a glacier that abuts one end of the lake. The lake ice averages 15 feet thick. During the Antarctic summer, the dark fur of the freezedried seals absorbs sunlight, and the slightly warmed bodies gradually melt the ice around them. In the process they might sink several feet into the ice until they reach an equilibrium point where the sun's rays no longer deliver enough heat to melt the surrounding ice.

Then the processes that give other seals Arthurian burial rites come into play as the lake ice evaporates from the top and freezes from the bottom. Eventually, the seal carcass starts rising, pushed up from below by the newly frozen ice, and as the body approaches the surface the ice evaporates above it. The process continues until the seal reaches the surface, but unlike the seals shipped out to sea by calving from the ice shelf, these freezedried mummies are unable to leave the lake. And so the whole cycle begins anew. From the perspective of puny human time scales, this extremely slow-motion bobbing can go on forever.

In 1996 I visited the Dry Valleys as part of a National Science Foundation fellowship program that brings writers and artists to Antarctica. “Dry” is an understatement—it's likely that it hasn't rained there for more than 2 million years. There's precious little precipitation anywhere on the continent, and the valleys are the driest place in Antarctica. Almost all of what meager water vapor gets picked up from the Ross Sea has been wrung out of the air as it travels over the enormous East Antarctic Ice Sheet before it gets to the Dry Valleys.

The valleys form a basin, and tiny amounts of meltwater flow—if that's the word—into Lake Vanda, the lowest point in the area. Most of that flow comes from the Onyx, Antarctica's mightiest river. Crossing the river during “flood” requires one large step for most adults, and the river flows only a few days each year.

The trip to the Dry Valleys was perhaps the most memorable part of my itinerary, which also took me to the edge of the Ross Ice Shelf, a research station on the West Antarctic Ice Sheet, and the South Pole. As always in Antarctica, I was bundled up in clothes issued by the NSF reflecting the latest thinking of their cold-weather specialists. Apart from multiple windbreaking, thermal and insulating layers, I also wore a balaclava and hard-shelled “moon” boots designed for extreme cold. It was a bit cumbersome but effective.

Clothing merits a short digression, because strict rules concerning it are the visitor's first indication of the extremes to be encountered in Antarctica. The National Science Foundation insists that visitors wear NSF-issued clothing and adhere to its rules on how it is to be worn. Some of the most frightening nonfiction writing available comes from the drily written guides supplied by the NSF for visitors to the continent, which methodically cite the dangers that lurk—ranging from being flash-frozen by a ground blizzard to losing limbs to helicopter blades—should one be so foolish as to fail to dress properly for the weather or to ignore safety precautions.

The resident scientists treat the cumbersome bureaucratic procedures as a necessary evil. When I asked for some paper prior to my trip out to the Dry Valleys, one scientist joked, “Oh, you have to fill out a 1047-3 requisition form,” while another chimed in, “And be sure to take the paper-cut training course.”

I was lucky enough to escape any truly bad weather during my visit, but some of my fellow travelers did not. When I visited a camp on the West Antarctic Ice Sheet, the weather was sunny and the wind low. A producer from the BBC told me that when she went to the same site a week later, her hands froze to the point that she couldn't zip up her pants following a trip to the latrine. Another journalist recalled his latrine experiences when he went to Meteorite Alley, a place so scoured by the howling winds that geologists go there to collect meteorites deposited millions of years ago. He said it was so frigid that a trip to relieve oneself was a highly choreographed affair, during which the principal actor waited until the point of peak urgency before making a mad dash to the latrine and consummating the transaction in a matter of seconds. In Antarctica even the simplest bodily functions require planning and involve risk.

My luck with the weather held when I went out to the Dry Valleys, although this was not that surprising since, by its very nature, the area is spared some of the sudden and dangerous storms that appear out on the ice sheets. The valleys rank among earth's simplest ecosystems.

In an unfortunate parody of the slogan “What happens in Vegas, stays in Vegas,” the Dry Valleys are so simple that a visitor can retrace the paths of expeditions from the 1950s simply by looking at the ground. What the Dry Valleys get, the Dry Valleys keep, and that includes footprints and trash. The NSF realized this years ago and instituted a strict carry-in/carryout policy that applies to everything, including sewage, although the scientists I spoke to complained that their efforts to keep the region pristine were regularly undermined by tourists flown in from Russian cruise ships who traipsed around, heedless of the extraordinary vulnerability of the area.

Still, the resident scientists try their best to tread lightly on the land. Those who stay there for the scientific season, the summer, make do with an absolute minimum of material comfort. Setting aside the cost of having goods delivered, if the rest of the developed world lived like scientists in the Dry Valleys, the price of oil would probably be $2 a barrel, and no one would be worried about running out of resources.

The Dry Valleys are frozen in time. About a hundred glaciers poke their noses into the valleys, but that's as far as they get, as all are frozen solid to the earth beneath them. Ice is pushed forward into the valleys over the frozen base, but an exquisite balance of precipitation, melting and evaporation keeps them almost exactly in place. With the bottom of the glacier stuck, the incoming ice folds over the top. An ultra-slow-motion camera would show the glacier to be “moonwalking,” à la Michael Jackson.

I saw dramatic evidence of this when I went into a tunnel that a glaciologist, Howard Conway of New Zealand's University of Auckland, had bored into the base of the Meserve glacier. Meserve has been stuck in roughly the same position for a million years. At the base of its terminus is a roughly 20-meter apron of ice that consists of shards shed by the hill-like front face of the glacier. Conway remarks that the spot at the edge of the apron is roughly where the glacier terminated 15,000 years ago as the last ice age wound down. A little farther out is a moraine that contains volcanic ash dated to 3.7 million years ago, and not far beyond that is another moraine that is even older. This moraine is so ancient that its boulders have been pulverized to gravel solely by the action of the wind.

Conway dug his tunnel in 1995. All glaciers have dirty layers at their base, as the mass of ice picks up detritus from the earth, and lower layers of the ice fold as the glacier makes its slow progress. Conway wanted to look at the dynamics of this folding in part so that scientists who drill holes in glaciers and study ice cores for clues to ancient climates could have a better idea of whether and how folding skews the record of the past as the coring samples are taken from ice closer to the bottom. (If the ice has folded over itself, for instance, the ice core record would produce what looked like extreme gyrations in climate when none in fact took place.) Because of the extraordinary stability of the Dry Valleys, Meserve offered a perfect site for Conway to examine this problem.