关于北极熊中学生英文演讲稿

Unlike Black and Grizzly bears, which are primarily nocturnal, the Polar Bear may be active at any time of the day or year, searching for prey on long summer days and sometimes on long winter nights. Adaptations to its Arctic habitat include its fur color, which blends with the snowy environment and so provides useful camouflage for capturing prey; its large size, which helps maintain body temperature by reducing surface-heat loss; and its furred feet, which insulate against cold and provide traction on icy surfaces. Because the hairs of its waterproof coat are hollow, they are especially insulating and increase the bear's buoyancy when swimming. An excellent swimmer, it paddles at about 6 1/2 mph (10 km/h) with the front feet only, hindfeet trailing-a trait unique among four-footed land animals-and can remain submerged for about two minutes. While swimming or treading water, it stretches its long neck for a better view, as it does on land. Owing to the scarcity of plants in its