Of all the seals in the world, only one, the leopard seal, has the reputation of a true hunter, a top predator. At up to 12 feet (four meters) long and more than a thousand pounds (450 kilograms), it moves with surprising agility and speed, often along the edges of ice floes, patrolling for penguins and other prey. "Sea-leopards," early explorers called them. A "fierce, handsome brute," wrote Frank Worsley, Sir Ernest Shackleton's skipper on the famous 1914 Endurance expedition. The name comes from the seal's patterned skin, which Worsley described as "a fawn coat spotted all over with brown markings."
Every austral summer, leopard seals wait in shallow water off major penguin breeding colonies to capture newly fledged birds going to sea for the first time. The seals' teeth tell the story: front canines and incisors designed to capture and shred their prey; back molars with sharp edges for grasping and cutting, but also with interlocking cusps to sift krill. The seals have a surprisingly diverse diet: krill, penguins, other seals, fish, and squid—anything they can get their canines on. The other seals on the menu are crabeater seal pups, or, off the island of South Georgia, Antarctic fur seal pups.
Leopard seals have been seen as far north as the coasts of Australia, South America, and South Africa. Their true home is circumpolar Antarctica, where they seem to fill more space than their actual size. Think of tigers in India, lions in Africa, grizzly bears in North America.
Göran Ehlmé, a Swedish cinematographer, has spent years in the water with leopard seals: "It's not strange that the seal has the reputation it has. The first time I saw one, I got scared. The big head. The large mouth. The sinister eyes. The icy water added to the fear. I had to rethink things through a bottle of whiskey and a long sleep."
Ehlmé had heard stories. He knew about a leopard seal attack on a member of Shackleton's crew, Thomas Orde-Lees, who was skiing across sea ice when a leopard seal emerged from between two floes and lunged after him in bold, snakelike movements. Orde-Lees managed to keep ahead, kicking and gliding, until the seal dived into an open lane of water and tracked him from below—following his shadow—to pop up ahead. Orde-Lees turned and yelled for help. The seal pursued until it was shot dead by Frank Wild, Shackleton's second-in-command.
The seal's reputation took another dark turn in July 2003 when Kirsty Brown, a 28-year-old marine biologist snorkeling off the Antarctic Peninsula, was grabbed, pulled down, and drowned. Her colleagues worked for an hour to revive her, but could not.
Leopard seals had punctured inflatable boats. They had now and then harassed people. But never before had they caused a documented human fatality.
"It makes a better story to tell about a ferocious animal than it does to tell about a curious one," says Ehlmé. "People tend to judge animals in frightening moments. But these seals, they are mostly curious. I tell other divers, 'If you get scared, just close your eyes. Then open them. The seal won't bite you, but it will be very close.' " (Antarctic research stations now advise anyone not studying leopard seals to postpone a dive, or to get out of the water, when they see one nearby.)
Photographer Paul Nicklen took Ehlmé's advice as he slipped into the cold sea of Antarctica and found an animal capable of ferocious acts and delicate gestures. Before his eyes a leopard seal—sometimes only inches away—would shred a penguin, or offer it to him whole.
As Shakespeare wrote in Othello, a reputation is "oft got without merit and lost without deserving." Perhaps it comes down to this: We cannot know a seal, or any wild animal, until we gently enter its home, where it keeps the truest part of itself. In so doing we learn more about ourselves, another top predator, forever curious.