Polar bears prefer eating blubber to meat.

　　对于北极熊来说，鲸的脂脂比肉更有吸引力。

　　Polar bears

　　北极熊

　　Polar bears live mainly on the Arctic pack ice, moving south in winter as the ice extends and north in summer when it melts back. Their white fur camouflages them on the ice, helping them stalk prey without being seen. Under the fur, their black skin absorbs heat. Hollow hairs and a thick layer of blubber (fat) also keep out the cold.

　　北极熊主要生活在北极的大块浮冰上。它们在冬天冰层延伸的时候向南方迁徙，夏天冰层融化的时候又回到北方。它们的白色皮毛在冰面上是很好的伪装——帮助它们在不被猎物发现的情况下接近目标。在皮毛下面，它们黑色的皮肤可以吸收热量。中空的体毛和厚厚的脂肪层也能帮助抵御严寒。

　　Zoom in on…

　　放大镜

　　Scavenging

　　Each autumn, polar bears arrive at the town of Churchill, on the edge of Hudson Bay. They have spent summer in the forest, but hunt on the ice in winter. If the ice is late forming, they hang around the dump. They sometimes enter the town and make a nuisance of themselves.

　　每个夏季，北极熊会到达位于哈德森湾边缘地区的丘吉尔镇。它们在森林里度过夏天，却在结冰的河面上进行捕食活动。如果河水结冰比较晚，它们会在事先储藏食物的地方消磨时光。人们对偶尔闯入城镇“做客”的北极熊并不欢迎。

　　Q: Can polar bears swim?

　　问：北极熊会游泳吗？

　　A: Yes! Despite their ‘doggy paddle’ swimming style, polar bears are fantastic swimmers. They are true marine mammals and can swim many kilometers from one ice floe to another. To help them to do this, their coat is water repellent and their feet are partly webbed.

　　答：是的，抛开它们“狗扒式”泳姿不谈，北极熊是不可思议的游泳高手。它们是真正的海洋哺乳动物，从一块浮冰到另一块，北极熊可以游上很长的距离呢！北极熊能完成这样的浮冰漂移，是因为它们的皮毛外衣是防水的，而它们的脚部分是网状的。

　　A female polar bear gives birth, usually to twins, in a snow den in winter. After eating little all winter, she is hungry and must hunt seals to put on weight and produce milk for her cubs. But she must be careful. If a male bear spots them, he will attack the mother and kill the cubs.

　　冬天，雌性北极熊会在洞穴里生育，通常都会产下双胞胎。在整个冬季没有好好吃东西的情况下，雌性北极熊非常饥饿，它们要捕食海豹来增加重量，同时产生奶水来哺育幼熊。但是它必须小心，如果其他雄性北极熊发现它们，北极熊妈妈会受到袭击，小北极熊也有可能被杀死。

　　Awesome facts

　　惊人事实

　　When stalking seals on the ice, a polar bear was once seen to cover up its black nose with its furry paw so that it could not be seen!

　　当北极熊在冰面上捕食海豹时，它会用白色的前爪遮住黑色的鼻子，以此避免因为颜色的差异而被发现！

　　Hooded seal mothers feed their babies milk for just one week!

　　冠海豹妈妈只在小海豹出生的头一个礼拜给它们喂奶！

　　On the ice

　　冰原之上

　　Seals are mammals. They get oxygen from the air, so they must return to the surface regularly to breathe. In the spring, they leave the water to pup (give birth) in snow or ice dens or on top of the ice itself. When out of the water, Arctic seals are in danger of being eaten by the region’s number one killer-the polar bear.

　　海豹属于哺乳动物。它们从空气中获得氧气，所以它们必须不时地回到海面上呼吸。春天，它们离开海水，到冰雪形成的洞穴里面——甚至干脆独自到冰山的最高点进行生育。一旦离开了水，北极海豹就面临着被区域头号杀手——北极熊吃掉的危险。

　　How many male hooded seals can you count?

　　你可以数出多少只雄性冠海豹？

　　Hooded seals live in the Arctic. At breeding time the males display to females and to one another. They do this by blowing out the lining of one nostril into an outsize red balloon or by inflating their black nose hood.

　　冠海豹生活在北极。在繁殖时期每头雄冠海豹向一只又一只的雌冠海豹求偶。它们用两种方法来表达自己的目的：将一个鼻孔的内膜向外吹成一个红色的气球，或者拼命胀大它们那黑色鼻翼。

　　Seals maintain open holes in the ice so that they can breathe regularly. A polar bear may sit for hours at a breathing hole, waiting for a seal to surface. As soon as it does, one swipe from the bear’s powerful forepaw will haul the seal out onto the ice.

　　海豹的窝都是保持敞开状态的，这样它们可以不时地透气。一头北极熊会在呼吸口边坐上数个小时等待海豹出来换气。只要海豹把头探出来，来自熊掌的重击就会把它掀到冰面上。

　　Escape hatch

　　安全孵化

　　Ringed seal pups are reared in snow dens. Each den has an escape hath to the sea. Polar bears can smell the seals and break in the roof, so a mother often has several dens. She leaves some empty to confuse the bears.

　　环斑海豹通常在洞穴的底部生育。每个洞穴都有一个通向大海的“紧急出口”。北极熊可以闻到海豹的气味并打破洞穴的顶部，因此海豹妈妈通常都有好几个洞穴。它会留下一些空的洞穴来迷惑北极熊。

　　Walrus males use their tusks for displaying to females and for hauling themselves out onto ice floes.

　　雄海象的长牙有两大功效：求偶，以及将自己笨重的躯体从海里托到冰面上。

　　Zoom in on…

　　放大镜

　　Walrus

　　海象

　　In summer, hundreds of male walrus haul themselves out onto Round Island, Alaska, to sun themselves. When they leave the water they are pale grey. This is because the blood withdraws from their skin in cold water so that they don’t lose heat. As they warm up on land, the blood reaches their skin and they turn bright pink.

　　夏日，数以百计的海象来到阿拉斯加的环岛晒太阳。离开海水的时候，它们的体色是浅灰色的，因为在冰水中它们的血液不进行皮肤循环以保证热量不会流失。当它们在陆地上暖和了以后，血液又重新循环，使它们的体色变成了亮粉红色。

　　The leopard seal is one of the Antarctic’s fiercest marine predators. It stakes out penguin colonies and grabs the birds when they enter the water. It throws its victim into the air and skins it alive before swallowing the flesh.

　　豹海豹是北极最凶猛的海洋捕食者之一。它监视着小企鹅的行动，捕捉那些进入水中的鸟类。它把猎物抛到空中，在猎物活着的时候把它们的皮剥掉，再把它们吞到肚子里。

　　The Weddell seal patrols an under-ice territory, which it defends by making a singing noise. It has a breathing hole that it must keep clear, using its teeth to chisel away regularly at the ice. Eventually, its teeth wear down or rot and the seal dies because it cannot keep its ice hole open.

　　威德尔海豹巡视其冰层之下的领地，它们用自己独有的奇特歌声来划分领地。威德尔海豹有一个保持通畅的呼吸口。它们会经常到冰面上用牙齿去清理呼吸口。有时，当威德尔海豹的牙齿磨损或者腐烂了以后就可能会死去，因为它们失去了清理呼吸口的工具。

　　Seal patrols

　　巡视的海豹

　　Seals appeared in the northern hemisphere about 30 million years ago. During a cold period in the Earth’s history, some headed south. Today, the crabeater seal population in the Antarctic is the largest in the world-possibly more than 15 million seals-making it the most numerous large mammal on the planet after humans.

　　海豹早在300万年前就在北半球出现了。在历史的寒冷时期，一些海豹向南方迁徙。如今在南极洲，食虾海豹的数量是目前世界上最多的——可能超过了150万只。这让它成为了地球上继人类之后数量排名第二的哺乳动物。

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