這是《動物王國大探險展》極地生態區的北極熊導覽。在此聆聽這位冰原上的頂級掠食者。
上方可播放導覽語音。逐字稿與語音內容相同。
This is the polar bear stop in the polar gallery of the Animal Kingdom Grand Adventure Exhibition. Listen here to the top predator of the ice.
Play the narration above. The transcript matches the audio.
漫天飛雪的北極裡，一個龐大的身軀悄悄步入冰原，正偷偷出現在海豹身後，準備捕食，牠是極地世界中的頂級掠食者：北極熊。
北極熊看似有一身潔白如雪的皮毛，但牠們的毛不是白色，而是透明中空的。看起來白色，是因為光線進入毛髮內部後產生散射，所造成的光學錯覺：毛髮下的皮膚是黑色的，能將陽光熱能吸收到最大化，提供極佳的保溫，並讓體表熱量被包覆在體內，所以當科學家用紅外線照相機追蹤時，牠們就像是完全隱形。
北極熊的腳掌上還有特殊的小突起，科學家稱為「乳突構造」，能增加與冰雪表面的抓地力和摩擦力，雖然牠們的掌墊比例比其他熊類更小，但這是為了禦寒，防止熱量流失，也因為這些像雪地防滑輪胎一樣的腳掌，讓北極熊能在光滑如鏡的冰面上高速奔跑。
全球暖化導致北極的海冰正以驚人速度消融，北極熊的生存是一份迫在眉睫、關乎地球生態未來的提醒。
In an Arctic of flying snow, a huge body steps quietly onto the ice, appearing behind a seal, ready to hunt. It is the top predator of the polar world: the polar bear.
The polar bear seems to wear a coat as white as snow, but the hair is not white; it is clear and hollow. It looks white because light that enters the hair scatters, an optical trick. The skin under the hair is black, and can take in the heat of the sun to the utmost, giving excellent warmth and wrapping the heat of the body inside. So when scientists track them with an infrared camera, they seem completely invisible.
On the soles there are also special small raised points, which scientists call papillae, that add grip and friction on ice and snow. Their pads are smaller in proportion than those of other bears, but that is to keep out the cold and stop heat from leaving; and because these paws are like snow tires, the polar bear can run at speed on ice as smooth as glass.
Global warming is making the sea ice of the Arctic vanish at a startling rate. The polar bear's survival is an urgent reminder, close at hand, of the future of the Earth's ecology.