From its emergence into the world as a 5-inch egg to its adulthood as a 4-foot-tall, 90-pound marine bird, life for an emperor penguin might best be described, using the words of Harvard mathematician Martin Nowak, as “a snuggle for survival.”

Females of the species, Aptenodytes forsteriis, lay their eggs in colonies on the shore-fast sea ice of Antarctica in late May or early June—the onset of Austral winter, when temperatures can plunge below -50 degrees Celsius (-58 degrees Fahrenheit), and winds exceed 137 kilometers per hour (85 miles per hour). Females must then find food to replenish their reserves, so, before embarking on journeys dozens of miles back to the open ocean, they carefully transfer their developing progeny onto the feet of their mates.

It is the male that then carries the baby through the darkest winter months of June and July while the female forages—carefully keeping the egg off the cold sea ice, snugging it over with a pocket of skin on his lower belly called a brood pouch, and rotating it gently as he shuffles along to ensure even heating. When temperatures are cold enough that even thick feathers—the densest of any bird on Earth—aren’t enough, males huddle together in great masses, as seen in this earlier bioGraphic film, their bellies inward toward the center, their faces tucked between the shoulders of the bird in front of them. At times, they fall silent to conserve energy, their shifting feet the only sound. The center of this great, teeming hug can reach temperatures up to (37 degrees Celsius (98.6 degrees Fahrenheit)—plenty hot enough to keep dad warm as he loses as much as half his body weight from fasting—and plenty hot enough to ensure the egg atop his feet is well-incubated until it hatches.

As such, the male is careful to only occasionally turn away from the melee and lift his brood pouch to check on his progeny. Photographer Stefan Christmann had just 20 minutes of daylight to capture the fortuitous moment when one did so in the 10,000-penguin colony on Atka Bay, 2,700 miles south of the southern tip of Africa. The result was an image of a chick’s first look at its frigid new home. “This image says to me that nothing is impossible. These almost naked chicks are born into the coldest habitat on the planet and yet they manage to survive as part of the colony,” writes Christmann, who spent the winters of 2016 and 2021 on Atka Bay and published a richly illustrated book about his experiences. “Emperor penguins are prime examples of how teamwork can help to overcome even the most difficult obstacles.”

When females return at the end of polar night, they take over parental duties, hustling the babies onto their own feet, and feeding them regurgitated food from their months at sea while the males head for the water. And when the chicks are old enough, both mates leave to devour squid, fish, and krill. In their absence, the downy chicks practice their own little huddle called a crèche, clumsily jostling each other for the center position in what Christmann once described to National Geographic as “a really cute mess.”

Counterintuitively, though, global warming is increasing the likelihood of emperor penguin chicks freezing to death, and the IUCN categorizes the species as Near Threatened. Rising air and ocean temperatures are destabilizing the sea ice that an estimated 250,000 emperor penguin pairs rely on each winter. Should the ice break up before the chicks have molted their baby down and grown waterproof adult feathers, they would be swept into the sea to die. Climate models project a 30 to 40 percent loss of sea ice in the second half of the 21st century if warming trends continue unabated. Some scientists have predicted up to an 80 percent loss of penguin colonies by 2100.

No one knows for sure whether the species can adapt to these changes. In one hopeful sign, two colonies do exist on land, and have been stable for 20 years. The penguins’ hardiness can’t hurt either: In addition to their cold tolerance, they can dive to depths of nearly 610 meters (2,000 feet) for as long as 20 minutes when foraging. Some have swum as far as Tierra Del Fuego, the Falkland Islands, and New Zealand. And then of course there’s their tremendous community spirit. They are after all, as Christmann writes, “birds made of love.”