‘Why?’
‘I don’t know, but it works.’
‘What makes them so aggressive?’
‘We don’t know that either. You might think they had high levels of testosterone, but in fact it’s pretty low. Probably because testosterone is expensive. It suppresses your immune system and down here you can’t afford to get sick.’
He backed off and the mother settled on the nest, rolling the egg carefully back into the puddle of water. Olivier shrugged fatalistically and we moved on.
Now we were walking up the rocky hillside, skidding on penguin guano and slushy snow, carefully stepping over the conduits that hid the network of cables keeping the station alive. ‘Snow petrels have the same problem with meltwater,’ Olivier said. ‘There’s fierce competition for the best nesting sites—the ones that are sheltered from snow or drain water well. The birds live forty years or more, so it’s tough for young new breeders.’
Researchers had been banding both chicks and adults here since 1963. It was impossible to tell how old the adults were when they were first banded, but when they settled into a nest site you could then watch them for the rest of their lives. ‘They are very faithful to the nest each year. If a bird is missing for two years it’s probably dead. They don’t breed elsewhere. If you destroy a breeding site, they won’t breed for the rest of their lives.’
The colony was a regular bank of rocks, just like all the others, except that many of the crannies and hollows held birds. They were a little smaller than doves; their beaks, feet and eyes were black and the rest of them was snow-white.
Olivier told me that, like Thierry with the Adélies, he wanted to understand what inner hormonal signals drove the snow petrels. They, too, shared parental duties, and if their mate was late they had to make exactly the same decisions as the emperors and the Adélies. This summer, he was studying the stress hormone corticosterone to see if it played the same role here, too.
‘Many other birds have a totally different strategy. Robins, say, or blackbirds, only live for a couple of years, and they lay four, five, even six eggs at a time. But all the birds here are so long-lived that their strategy is to favour their own survival over that of their chicks. A snow petrel can go five, six years without breeding. They only lay one egg and won’t re-lay if they lose it. Even if no chicks survive for one year, the population can still be stable because the parents don’t take risks. Their priority is their own survival—there will be many more chances to breed.
‘We think corticosterone is the key. But it might depend on age, too. Young breeders are very prudent. But if the older ones have only one or two seasons left in them, they might take a few more risks.’30
He told me that the science was surprisingly easy to do here. Since good nest sites were so hard to come by, and possession was most of the law, snow petrels incubating eggs were reluctant to leave their nests for any reason. That made them easy to catch. They were so attached to the nest site, they wouldn’t even try to fly away.
They would, however, fight. Young birds challenged the owners all the time for good sites. As we walked through the colony one such youth decided to try its luck. It launched itself at the nearest nest possessor with a fierce flurry of beak and wings. Now the two of them were shrieking, stabbing brutally with their beaks and scratching with their claws, grappling and rolling over each other like cage fighters egged on by a crowd.
Olivier was right. In spite of their angelic appearance, they were more vicious than the skuas. But it was about to get even worse. The owner of the nest threw back its delicate white head and splat! A glob of bright orange goo emerged from its beak, arched through the air and landed squarely on its opponent’s back. Splat! There went another one, this time barely missing the recipient’s eye. The poor creature was vanquished. It yielded hastily and our hero returned to its nest with something like a swagger.
These graceful birds spit? Olivier grinned at my shocked expression. ‘It’s an effective weapon for them,’ he said. ‘They use oil from their food to make the spit and it’s bad for their feathers.’ We both watched as the unfortunate recipient of those lurid orange gobs rushed off to roll on the snow and try to get clean. ‘Some birds can be lovely,’ Olivier remarked. ‘When you lift them to check their leg ring they will gently preen your hand. Others see you and spit immediately. And the spit stinks—which is why we’re the smelliest people on base.’
He said this cheerfully, as though it was a badge of honour. ‘I’ve kept the jacket from one winter I spent here. It still smells fourteen years later. When I’m in a bad mood at home I get it out and smell it and remember.’
Olivier was still investigating which hormones drove the snow petrels to fight, and which made them yield for the year. And he told me that emperors too could be victims of raging hormones. ‘Failed breeders can kidnap chicks. There can be up to five or six adults fighting over a chick and quite often the chick will die. Or they can adopt a chick for a few days and then kick it off. We think this might be because of another hormone behind parental care—prolactin. When the female emperor returns after two months, she has no idea if the incubation has been successful. So she has to have lots of prolactin to keep the urge alive. Then the male goes off foraging for a month and has to be motivated to return.’
Emperors also have an inbuilt hormonal trigger for when to quit. They will always abandon their eggs or chicks rather than risk their own lives, and of the owl-eyed chicks that crowded confidently around me yesterday, fewer than one in five will make it to adulthood. ‘Some emperors are more than forty years old. Like snow petrels they’ll have many more opportunities to breed. It’s better to fail one year but stay alive.’
It was better, in Shackleton’s words, to be a live donkey than a dead lion.
That evening after dinner there was another movie showing, but I slipped out again and walked down to the sea. I diverted past one of Olivier’s snow petrel colonies. They were beautiful still, and their spitting didn’t make them less so. It just gave them bite.
Down by the sea there was the usual procession of Adélies, trotting down the snow paths, queuing to jump into the quiet waters and stock up on fish to feed their hatchlings. I watched them for more than an hour; the leaps looked dramatic but made almost no sound, and the whole scene was deeply peaceful. They knew what they were doing, these little beasts. No wonder they had no self-doubt. Like the Antarctic heroes of old they would battle against extraordinary odds, survive appalling conditions and push themselves to the limits. But like the emperors and the snow petrels, too, they had also inherited another important lesson from their forebears, and it was the same lesson that Shackleton had to swallow just a hundred miles from the Pole. To survive down here, you also have to know when to quit.
Eventually, my muscles stiffening, I got up and started to walk home. But I had the feeling that someone was watching me. I turned abruptly. One of the Adélies was about six feet behind me, staring up at me, motionless, unblinking. I turned again, walked a few hundred feet and then quickly looked back. The penguin had matched me step for step. It was standing there, perfectly still, six feet behind me, looking up with that same measured stare. We repeated this game once, twice, three times. It was playing statues with me. Each time I turned it was motionless. Each time I walked, it walked with me.
We were almost back at the dorm now, and it had followed me all the way. I remembered David Ainley saying that Adélies treat you as if you were an overgrown penguin, and how I thought at the time that he seemed to see himself the same way. I looked down again at this little creature and it looked unflinchingly back at me. I don’t know who was anthropomorphising whom, but—though I stepped inside the dormitory and closed the door firmly—I knew that I had succumbed. Penguins have melted stonier hearts than mine. I never stood a chance.
3
Mars on Earth
The McMurdo Dry Valleys are the closest thing we have on Earth to the planet Mars. A set of bare rocky valleys running in paral
lel from the edge of the ice sheet down to the sea, they are ‘dry’ not just through lack of water, but through lack of ice. They are also all but monochrome. The jagged mountain ranges that separate the valleys are run through like a layer cake with alternate slabs of chocolate brown dolorite and pale sandstone. This is an unearthly place, intimidating and harsh in the bright light of noon. But at night in the summer, when the sun never sets but merely hovers close to the horizon and casts its long low shadows, the peaks seem to soften, the dolorite rock grows richer and the oatmeal sandstone takes on a golden glow.
It’s not just the colours that look their best at night-time. Those long shadows also pick out the features that tell the history of this extraordinary place. There are weird raised beaches, jutting out halfway up the mountain sides, which mark ancient high stands of water; rock ripples and gigantic potholes that were once carved out by a waterfall the size of Niagara; and bulbous glaciers and frost-cracked soils that show how cold and dry this land has now become.
Fifty-five million years ago, Antarctica was warm, wet and brimming with life. The surface shifted and shuddered, driven by grinding tectonic forces in the crust beneath. As the crust tore, this part of the ancient world lurched upwards. And with the rising land, the rivers on its surface now had something to get their teeth into. They cut down into the raised rocks, carving out this set of parallel valleys as they surged from the interior to the sea.
Meanwhile, tectonic happenings on the other side of the soon-to-be continent were beginning to make themselves felt. After millions of years of gradually separating itself from the rest of the world’s land masses, Antarctica had only one remaining point of contact: the long thin arm of the Antarctic Peninsula was still clinging on to the southern tip of South America.
And then, some thirty-five million years ago, it slipped its hold. Seas surged between the two former partners, and currents began to swirl around the new continent, building up into a vortex that cut it off from the warmth and comfort of the outside world.
The opening of Drake Passage had slammed Antarctica’s freezer door shut. First its trees disappeared, then its tundra faded to dust. To the south, up on the Antarctic plateau, a mighty ice sheet advanced towards the coast. It would have swamped the valleys but a saw-toothed range of mountains, thrown up along their southern edge by those earlier tectonic convulsions, stopped the ice sheet in its tracks. Instead, the valley floors stayed bare, growing steadily colder and drier. A few small glaciers built up from snow banks on the mountains, and spilled down on to the valley floors. Cold air poured down from the plateau in the form of mighty winds that scoured and shaped the rocks, carving holes in them that whistle eerily. No rain has fallen in the interior of the Dry Valleys for millions of years, and there has been precious little snow. This is the coldest, driest, barest patch of rock on Earth.
That alone would be enough to excite many scientists. To understand our home planet, people always want to go to the extremes. But the DryValleys have something more alien to offer. For the history of this region mirrors the early history of Mars, one of our nearest, and most intriguing, extra-terrestrial neighbours. Like the Dry Valleys, Mars once had liquid water on the surface, and was possibly also warm. Its surface is still cut through with channels where water once ran, basins that were once giant lakes, and beaches that once marked out ancient seashores. Now, though, its average temperature is -67°F and it is one of the driest places in the Solar System. That’s what’s really special about the McMurdo Dry Valleys. At some point in its life, Mars may have passed through the same stage that they are experiencing today.1 This is Mars on Earth.
And just as on Mars, there are no visible signs of life. True, you sometimes see the twisted, mummified body of a seal, its teeth bared in a rictus grin where the skin around the mouth has shrunk back. Nobody knows how old these mummies are, nor why the seals they once were took that wrong turning from the coast and perished up here for lack of food and water. But apart from them, the land is bare and apparently lifeless. When Scott first observed the valleys in December 1903, he wrote this: ‘It is worthy to record . . . that we have seen no living thing, not even a moss or a lichen; all that we did find, far inland amongst the moraine heaps, was the skeleton of a Weddell seal, and how that came there is beyond guessing. It is certainly a valley of the dead.’
His description was accurate, but his conclusion was dead wrong. The DryValleys are home to plenty of life, though it’s not as we usually know it. That’s because, though dry, the valleys are not entirely devoid of water. A few days each year the temperature there creeps above freezing, just long enough to melt a little ice from the glaciers that spill down into the valleys, and to make trickling streams that flow into long thin lakes on the valley floors. The lakes are, all of them, covered with a thick layer of ice; but they don’t freeze solid thanks to this small annual injection of liquid water, and warmth.
Where there’s water there is—usually—life. And this bleak landscape is already telling us extraordinary things about the possibility of life on Mars.
The valleys are just a short helicopter ride from McMurdo, and their unofficial capital is Lake Hoare in Taylor Valley. There has been a camp of sorts there since the 1970s, but the modern version, built in 1993, has three laboratory huts—one for radiation work, a general chemistry lab complete with fume hood for anything noxious, and an instrumentation lab bristling with electronics. Though residents sleep in tents, they eat and hang out in a further communal hut that is warm, spacious and jaunty with fairy lights. The camp manager, Rae Spain, fitted much of it out herself a few seasons ago when she worked here as a carpenter.
Rae was warm and welcoming, with a long blonde plait and a friendly smile. She was the archetypal camp mom. She had been coming to the ice since 1979, from the very earliest days that women fought their way on to the continent and into the programme. At first she intended to come just that one time, for the adventure. But she couldn’t get Antarctica out of her head. ‘It haunts you,’ she says.
Though it was technically a camp rather than a fully fledged base, the living and working quarters were unusually comfortable. Meals there were spectacular. After a hard day in the field you might come home to hand-rolled sushi, sesame chicken, miso soup or pork vindaloo, or a tasty barbecue with rosemary potatoes, carrot cake and freshly baked cookies. Then you could check your email (internet available 24/7), make a phone call anywhere in the world, or e-order something that would arrive by helicopter just a few weeks later. Camp residents might drink their water out of old jam jars, but this still felt more like the gimmick in a trendy pub than a disagreeable necessity. This was about as cushy as it got.
It was also a literary camp. I noticed Margaret Atwood novels on the shelves, and Rae told me she travels into Canada from her native Washington State to pick up books for the base. Next to the books were board games and piles of knitting yarns for the times when the weather closed in and there are no chores left to do. As with most parts of Antarctica, patience is a virtue here.
Rae had worked at all three of the main US stations—McMurdo, Palmer, out on the Peninsula, and the South Pole—but she was happiest here. It was even good, she said, on a bad day. Once someone had crashed an all-terrain vehicle into the edge of the lake, where the ice was thin and the water very close to the surface. The vehicle was wrecked and was going to have to be sling-loaded home on the base of a helicopter. Sling loads are always tricky. The helo doesn’t actually land. You have to stand beneath it like the Statue of Liberty, holding the hook from the chains high in your outstretched hand, balancing yourself against the downdraft and the noise, trying not to think about the massive hunk of metal hovering just above your head as the helo pilot inches down to reach you.
On this occasion, she got word that the helo was on its way so grabbed eighty pounds of chains and webbing and struggled onto the lake, crashing into melt pools until she was wet and frozen. She arrived at the vehicle to find that it was in pieces and needed to be rea
ssembled so had to send the helo away. And then she trudged back to the camp, dragging the chains miserably behind her, only to discover that the U-barrel had been overfilled with urine, and she had to try to siphon some off the top. But going outside, looking at the view, taking a few deep Antarctic breaths, she realised that even the worst day here was better than the best day back in Mactown. ‘After all, where else would I get a job as varied as this? Doing helo ops, building schedules, monitoring the generator and the solar energy systems, cooking food . . . burning shit.’
For yes, even that came under her purview. Rae lays out the Dry Valley rules to every new arrival, including those of the scatological variety, and the environmental regulations are strict. Solid matter goes into ‘rocket’ toilets that are burned in rotation. Pee goes first into a bottle and is then poured into large U-barrels. (One of the Antarctic rules repeated most often to newbies was this: Never ever drink from a bottle marked ‘P’.)
If you’re caught short out in the field you carry an empty pee bottle with you, and then bring the full one back to camp. Anything solid goes into plastic bags that you also carry with you. It’s best to avoid needing them, if you can. I’ve heard some useful tips about pee bottles. In the endless thermodynamic battle to keep warm in a cold place, one researcher told me that it’s always best to use a pee bottle during the night if you can. Any pee in your bladder costs you energy to keep it at body temperature. When the pee is in its bottle, on the other hand, you can even keep it with you in your sleeping bag, as a mini hot-water bottle. The science makes sense but I admit I didn’t try it.
You were also strictly forbidden to move rocks or stones, or to take any souvenirs. In this, as in all the Dry Valley environmental rules, there was no tolerance. Rae was a formidable exponent of the regulations. Though she was mild in appearance, I didn’t need to hear the stories about sling-loading to know she was made of steel when necessary. In the early days she saw off her fair share of foremen who didn’t think women should be on the ice, and tried to send her home. I would not like to be caught by her with an illicit souvenir in my pocket.
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