Each season, as the ever-thinning Arctic ice recedes, polar bears face a daunting challenge; Grizzly bears in British Columbia must use ingenuity and fancy footwork to collect their catch; The annual rains of the Serengeti draw in the greatest concentration of large animals on Earth; Each year, billions of sardines flood South Africa's east coast creating an action-packed feeding frenzy; Thousands of animals make the long trek toward the life saving annual flood of Botswana's Okavango Delta; The annual plankton boom of Alaska's coastal waters attracts humpback whales and sea lions, who must avoid predatory killer whales.