Free Antarctica by Gabrielle Walker

the message, the
Nimrod
had not yet sailed. It saw the signal and steamed to the rescue.
    When the ship arrived, Wild collapsed on board, but Shackleton hadn’t finished yet. Two of his men were still out there on the Barrier. He pulled together a rescue party and announced he would lead it himself. I can’t imagine how tired he must have been, how ready to fall, how relieved to be safe in the relative civilisation of the ship. But he wasn’t even tempted to stay and let others take over this one last act. He didn’t do it with any fanfare or in a showy fashion, but because he was a leader, and that’s what leaders do.
    Shackleton’s wife described him once as ‘a soul whipped on by the wanderfire’. 7 Perhaps that is true, but he was also whipped on by the drive to lead. Back in England, between expeditions, he seemed somehow diminished, a wide boy permanently full of foolish schemes to get rich quick. But on the ice he was magnificent.
    There is a tale, perhaps apocryphal, 8 that Shackleton had placed an advertisement in an English newspaper seeking crew for his
Nimrod
voyage:
    Â 
Men wanted for hazardous journey. Low wages, bitter cold, long hours of complete darkness. Safe return doubtful. Honour and recognition in event of success.
    Â 
    Throughout his subsequent Antarctic endeavours, Shackleton never once achieved what he had formally set out to do. But he nonetheless gained his share of honour and recognition. He went on to perform daring rescues, had extraordinary adventures, and—in spite of the advertisement—never lost a single man under his direct command.
    Within three years of Shackleton’s abortive attempt, two different expeditions had wiped out his southernmost record and succeeded in reaching the Pole, although one of them would not survive the journey back.
    â€˜Better a live donkey than a dead lion,’ Shackleton had observed to his wife. But he was no donkey. Turning for home, less than a hundred miles short of certain glory, was an act of extraordinary courage—one of the bravest things any Antarctic explorer has ever done.
    Roald Amundsen, the eventual conqueror of the Pole, understood this better than most. In his later account of his own expedition, Amundsen said this: ‘Ernest Shackleton’s name will always be written in the annals of Antarctic exploration in letters of fire.’
    Â 
    Beyond Shackleton’s hut, away from the main colony, lay a hollow between two small hills, where perhaps forty penguins were lying placidly on their nests inside a corral made from a green mesh fence that was thigh-high. This was a sub-colony, which David was studying separately from the rest. At first I thought the penguins were trapped, but then I saw a weighbridge, an archway over a metallic grey mat, piled around with rocks.
    This experiment was all about food. ‘Adélies are just bundles of energy,’ David said. ‘They keep going forward. Unless they’re sitting on eggs they just don’t stand still. It takes a lot of food, though. They definitely eat a lot of food.’
    He told me the birds there each had a chip inserted under their skin, the same sort that people use to identify their cats and dogs. The whole thing was ingenious. When a penguin entered the bridge, it cut through an optical beam that switched the machine on. A magnetic field in the hoop overhead activated the transmitter in the chip that broadcasted the penguin’s ID. Beneath the mat, an electronic scale measured its weight, and the bird then cut through a second beam so you knew whether it was entering or leaving.
    â€˜We weigh them in and out,’ David said. ‘When they’re feeding the chicks, we calculate how much food they give by comparing the adult’s arrival weight with its leaving weight. Doing that by weighing chicks causes too much disturbance.’
    The penguins eat a combination of fish and a shrimp-like creature called