King penguins at St. Andrews Bay, South Georgia.
"There are 400,000 king penguins in this one bay alone," says Frozen Planet director Chadden Hunter, who took the photo. By midday, the temperatures on South Georgia Island can reach a "sizzling" 60°F. That's hot for a king penguin. It's not unheard of for these heavily insulated birds to get heat stroke, so they've found ways to keep cool — by stretching out on the beach so that their feet can cool in the breeze.
An Arctic wolf on Ellesmere Island, Canada.
The Arctic wolves of Ellesmere Island are extremely remote and unused to humans. It took the Frozen Planet film crew many weeks before the wolves would allow them to get this close. Arctic wolves have roamed the northern latitudes for more than 2 million years. In spring, they catch small rodents, birds and hares to feed their pups, but this isn't enough; occasionally, they need to go after larger prey like musk oxen.
A pair of polar bear cubs swim for the first time.
When the pack ice breaks up in summer, six-month-old polar bear cubs have to learn to swim for the first time. Polar bears are actually marine mammals and are very at home in water as adults, but the summer thaw makes it a lot harder for them to hunt. In open water, polar bears no match for seals — their preferred prey. Seal hunting gets so tough during summer that polar bears resort to scavenging and even eating plants.
Antarctic fur seals clash on Bird Island, South Georgia.
In the height of summer, bull Antarctic fur seals battle for females. A single bull can control a harem of up to 15 cows — a prize worth fighting for. The fur flies during their epic battles for supremacy. These combatants can easily crush newborn seal pups, and frequently do. Roughly 95 percent of the world's population of Antarctic fur seals come to this island to pup and mate each summer. It's one of the densest gatherings of marine mammals on earth — 5 million of them at their peak.
Hoar frost forms on autumn leaves.
Hoar frost refers to the white crystals that form on cold, clear nights when heat losses into the open skies cause objects to become colder than the surrounding air. This often happens in autumn.
A beluga whale enjoys a body scrub.
In summer, thousands of beluga whales and their gray babies converge on Canada's Cunningham Bay each summer. When the tide is low, they swim into the rocky shallows and roll their bodies against the seabed. The gravel acts like a loofah, scraping off their old dead skin. Belugas are the only whales that moult each summer. The treatment keeps them clean and streamlined, and also seems to feel good.
A musk ox family in the Canadian Arctic.
Musk ox, which can weigh up to 900 pounds, are uniquely adapted to withstand the ferocious Arctic winters. They have a thick, double layer of fur to insulate them from the cold. They also have sharp horns for defense against predators, like wolves. In males, these horns meet in the middle to form a "boss," a thickened structure that protects their internal organs as they charge into one another headfirst during the mating season. These battles for supremacy are dramatic, but rarely fatal.
Aerial view of the beluga whale "spa" at Cunningham Inlet, Canada.
Every year thousands of belugas migrate to Cunningham Inlet from hundreds of miles away to have a body scrub in the shallows. Not only does this help the belugas shed their dead skin, making them more streamlined, it's also a good opportunity for the whales to socialize. The Frozen Planet team recorded an extraordinary range of calls and squeaks underwater as these "canaries of the sea" vocalized constantly while in the bay.
Adélie penguins on ice floes off the coast of Cape Crozier, Antarctica.
The Adélies' growing chicks require constant feeding, so the adults take turns leaving the colony to hunt for silverfish and krill off the coast.