The story of "Earth" is told through the eyes of three key animals: polar bears, elephants, and humpback whales. One of the story lines is the power of the sun and the strength of the seasons. The directors chose animals that were affected by the seasons of the planet. Global warming hits the poles first, and that's where it hits hardest. 

Starting with the polar bear, 700 miles south of the North Pole, the movie shows how the mother polar bear has to battle the naturally changing things in her environment. The polar bear and her two cubs struggle as ice literally melts below their feet. Similarly with the elephants, they have to undertake long, epic journeys through the desert, which is seasonal. The sun's annual rhythm drives the cycle of wet and dry seasons, which forces the elephants to be constantly on the move in search of fresh water.

In "Earth," it's the dry season, and thousands of elephants are struggling across the Kalahari. Thick clouds of dust blow across the desert, and there's a risk that a mother and calf will get separated in the sandstorm. The humpback whales travel from the equator down to the Antarctic, undertaking the longest migration of any marine mammal -- 4,000 miles -- to find nourishment in the waters. There's nothing for them to feed on when the waters are frozen, so they go to areas where the sun has melted the ice.

More About the Animals Featured in "Earth"
Humpback whales

• The humpback whales in the film migrate from warm waters of the tropics to waters off Antarctica where they feed on krill and small fish.
• Sometimes they feed on krill cooperatively using a method call "bubble netting." A circle of whales emit bubbles that gather the krill together and force them toward the surface at the center of the circle, making it easy for the whales to feed.
• Humpback whales' very small eyes help them withstand the pressure of a deep-sea dive.
• Instead of teeth, a humpback whale has approximately 330 pairs of baleen plates (fine brush-like structures), which strain krill from the water.
• Humpback whales are able to swim within 30 minutes of being born. Calves drink about 160 gallons of milk a day.

Polar bears

• Polar bears get all the liquid they need from their food (main source is the ringed seal).
• They will travel hundreds of miles in search of food and can swim 12 miles a day.
• They retain heat well and can't run long distances because of the danger of overheating.
• They are the largest land predator in the world. Males can grow up to about 8 feet and weigh up to 1,800 pounds.
• Even with their mother's care, only 50 percent of polar bear cubs survive their first year, and more are lost when they first leave their mother to make their way alone.
• The polar bears were filmed on Kong Karls Land, a group of islands between the Barents Sea and the Arctic Ocean.

Elephants

• Adult elephants can eat more than 300 pounds of food and drink 50 gallons of water a day.
• Their ears act as a cooling system. By holding them out in the wind or flapping them, elephants can increase the movement of air over their ears and cool the blood running through them, thereby regulating its body heat.
• It can take up to six months for an elephant calf to learn how to use its trunk to bring water to its mouth.
• In times of danger, adult elephants in a herd will form a ring around the young, facing out to protect them.
• In the film, the elephants spend weeks traveling across the Kalahari Desert to reach the abundant waters of the Okavango Delta, the world's largest inland delta, where the Okavango River empties into the desert.

Special Thanks
Special thanks to "Earth" directors Alastair Fothergill and Mark Linfield for chatting about their beautiful, one-of-a kind movie, "Earth," which comes out April 22, 2009. For every ticket bought within the first week of distribution (April 22-29, 2009), Disneynature will plant a tree in Brazil's endangered Atlantic Forest. So take the entire family -- you'll be making a positive impact on our planet!