Imagine, if you will, that you are standing in the centre of the Antarctic continent. It is the middle of winter. It is almost pitch black because the sun hasn’t risen for several weeks, and it won’t make an appearance for another few months yet. The only light comes from the southern lights – the aurora australis – as they flash and dance across the sky above. And even if there wasn’t perpetual darkness, you still wouldn’t be able to see a thing because of the swirling, week-long blizzards that are blasted around by 100 mp/h plus winds.
Oh, and did I mention that it’s cold? Exceedingly cold. We humans waste no time in complaining whenever the temperature in our country drops below freezing, so it’s hard to comprehend living in a place where the temperature rarely rises above freezing. In the depths of winter, the temperature in Antarctica can plummet to a mind-numbing -70°C or even more – enough to kill an exposed person in minutes, cause water to explode into ice crystals and make steel shatter. It’s hard to think of a place on the entire planet more inhospitable to life.
And yet, as winter approaches and virtually all life vacates the interior of the continent, one animal is just arriving: the Emperor penguin. As these flightless birds emerge from the sea and start heading towards their breeding grounds, they have a comical air about them as they toboggan across the snowy landscape, or begin their slow, waddling march. It’s easy to forget they are about to endure the worst temperatures on the planet.
100 Days of Winter
Upon reaching the breeding site – which can be up to 100 miles away from the coast – the penguins pair up and mate. There is no material in this desolate place to make a nest so the female, upon laying a large single egg, transfers it over to the male, who balances it on top of his feet. This needs to be done very quickly otherwise the egg will freeze. The male keeps the egg warm with his feathers and the female, deciding that she has done enough, returns to the sea to replenish her reserves.
Then the full brunt of winter hits. As the sun sets for the final time in three months and the temperature nose-dives, it’s hard to imagine that any animal, exposed as they are to the brutal elements, could survive such conditions. But the Emperor penguin is not an ordinary animal. Its 3cm-thick layer of insulating blubber may greatly restrict its movement on land – humorously so – but it helps keep its body temperature from falling. On top of that, it has a very dense layer of feathers – about 100 per square inch, the highest density of any bird – which can be erected to trap a layer of air close to the body, again adding much-needed insulation. Their extremities don’t get frostbite because the blood returning from a foot in contact with the cold ice is warmed up by more blood descending from the much warmer body core.
Even so, three months is a long time and the males are pushed to their absolute limit. They cannot feed at all during this time so their fat and blubber reserves begin to disappear. As they feel the cold more and more, the males all huddle together in huge groups for extra warmth, each taking it in turn within the sheltered middle and then the outer rim, where their backs are horribly exposed to the high winds. By the time the egg finally hatches, 64 days later, the male will have spent nearly a hundred and twenty days at the breeding site, not having eaten that entire time, and having lost nearly half of their body weight.
Often, the female won’t have returned to the breeding colony by the time the chick hatches so the male must feed his newborn on the last of his reserves – a curd-like substance sometimes known as crop milk. Only when she finally reappears, perhaps another week or so later, can the half-starved male be relieved of his duties and be allowed to go back to the sea to feed.
So why do they do it?
Why do Emperor penguins go through such terrible ordeals every year? Why don’t they breed in the Antarctic spring or summer like any other animal would, where the temperatures are at least slightly more tolerable? The answer lies directly in their size. At over 30 kg in weight, and over 4 feet high, the Emperor is the biggest penguin in the world – and there’s a good reason for that. Increased body size is an evolutionary adaptation to the cold. A body can only lose heat from its surface and so a big animal has a smaller surface area in proportion to its overall volume than a smaller animal. This means it takes longer for heat from the centre of the body to reach its surface, and so it can retain heat much more effectively. This is why the Emperor penguin, which lives at the South Pole, is much larger than other penguins that live in more northerly (and warmer) regions.
But big size presents a problem when breeding. The Antarctic summer is so pitifully small that if the Emperor penguin bred then, their large chick would not have time to sufficiently develop and fledge before the coldest winter on the planet arrived. So these birds, instead of starting their breeding cycle at the beginning of summer, must do so at the end. And they pay the price – only 19% of chicks survive their first year.
How would you define the Emperor penguin then? The world’s most dedicated father? The hardiest bird on the planet? Or maybe just the craziest? Whatever you want to call it, the Emperor penguin is in a league of its own; it’s the only large animal to face off against the Antarctic winter – and win.