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Global warming poses a special danger to the Arctic, a region in which wildlife and nature have formed a complex interrelationship. Now, this delicate balance is threatened by rising temperatures -- a threat symbolized by the plight of the king of the north, the polar bear. A major concern is the declining population of ringed seal, the polar bear's chief prey. Unseasonable warmth causes the snow dens of the seal to collapse, leaving their pups vulnerable. The warmth also shrinks the sea ice that is the bear's hunting ground, making it harder to find the seals during the short winter hunting season. A decline in its chief food source will result in a decline in polar bear populations, and biologists have already noted a drop in birth rates and suspect the bears' physical condition is worsening.
 The timing of migrations is critical to the survival of numerous bird species. Beginning their journey too early or late may mean that birds miss the food sources they need to survive.
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Migratory birds are already being affected by the changing climate. Scientists studying the dates on which red-winged blackbirds arrive in northern Michigan found that warming temperatures have dramatically altered the birds' migration. They now arrive 21 days earlier than they did in 1960.
Threatened aquatic species like manatees could also suffer. Manatees depend on grass beds in shallow coastal zones for food and habitat. As sea levels rise, this habitat will disappear, as will coastal marshes and wetlands worldwide. Key wildlife habitats like the Florida Everglades and Chesapeake Bay will likely be flooded out of existence. Warmer water temperatures may also spur the growth of deadly red tides, increasing the danger not only to manatees and other aquatic mammals, but to humans as well.