冬天的高纬度北极区 The high Artic in winter,
是地球上生存最艰难的地区之一 One of the toughest places on Earth in which to live.
只有三种顶级掠食者在这里生存 Only three top predators are able to survive here.
北极狼 正在冰冻荒原上寻找猎物 The wolf, searching for its prey over the frozen lands.
北极狐 在空旷的海岸边艰难维生 The Arctic fox, scraping a living on the empty coasts.
而北极熊生活在海冰上 And out on the sea ice, the polar bear.
为了在此常年生存 To live here, year round,
这些猎食者必须充分利用好机会 these hunters must exploit the good times
以此度过艰难的日子 so that they can endure the bad.
所有北极生命必须面对的一个重要难题 All life in the Arctic must face one fundamental problem.
不是严寒的气候 Not the cold,
而是无休止的季节交替 but the endless cycle of change.
当太阳在春天回归北极 When the sun returns to the Arctic in spring,
引发了地球上最壮观的季节变化 it launches the greatest event of seasonal change on Earth.
这主宰了世界上唯一海冰捕猎者的生存 A change that rules the life of the world's only sea ice hunter.
北极熊完全依靠海冰为平台捕猎 The polar bear is totally dependent upon the sea ice in order to hunt.
在接下来的三个月里 它必须摄入一年需要食物总量的 It must eat two thirds of the food it needs for the whole year
三分之二 in the next three months,
因为脚下的冰层很快就会融化 before the sun melts the ice from beneath its feet.
海豹是北极熊最主要的猎物 Seals are the bear's most important prey.
春季伊始 At the start of spring,
它们爬到冰层上产崽 they come out onto the ice to give birth to their pups.
在冰层下 它们不能离呼吸孔太远 Beneath it, they can't stray far from their breathing holes.
那样很容易遭到北极熊猎杀 That makes it easy for the bears.
但有利的时机转瞬即逝 But that window of opportunity is brief.
很快 海冰上遍布融化的冰孔 Soon, the sea ice is riddled with melt holes.
海豹幼崽已经长大到会游泳了 The seal pups have grown large enough to swim
然后在水中消失不见 and disappear into the water.
北极熊的日子变得极为艰难 It's increasingly hard-going for the polar bear.
现在 静卧休息的海豹被冰孔环绕 Now, resting seals are surrounded by holes in the ice,
因此它们能够选择逃跑路线 so they have their pick of escape routes.
一旦在水中 它们游泳的速度远超北极熊 And, once in the water, they can easily out-swim a bear.
每只海豹对周围海冰的动静十分敏感 Each seal is very sensitive to every movement on the surrounding ice.
北极熊只有利用冰孔尽可能接近海豹 A bear can only hope to get close enough to pounce
才有机会发动突袭 by taking advantage of the melt holes.
啊没有看起来那么容易 Ah Not as straightforward as it looks.
秘诀是找到离海豹最近的洞口 The trick is to find the hole nearest to the seal
避开海豹的视线 without popping up in view
然后发动突袭 and ruining the surprise.
只差一点 Almost there.
可是一旦在冰层下 But once under the ice,
很容易失去耐性 it's easy to lose your bearings.
哗啦 Blast!
慢慢来 Gently does it.
糟糕 Oops.
在春末的薄冰上 偷袭的成功率 Only one in five stalks is successful on this thin ice
只有五分之一 at the end of spring.
北极熊的最佳狩猎季节快结束了 The bear's best season is ending.
和澳洲大小相当的冰层即将崩解 An expanse of sea-ice the size of Australia will soon break up.
北极的最佳狩猎场已经不在海冰之上 The Arctic's best hunting is no longer out on the frozen ocean,
而在周围的陆地上 but on the land that surrounds it.
那里是另一种狩猎者的领地 And that is the territory of a different kind of hunter.
经过食物匮乏冬天和春天 After a lean winter and spring,
北极狼终于迎来了好日子 the good times have finally arrived for the Arctic wolf.
陆地上 邻近的夏天使积雪逐渐融化 On the land, the snow is melting away as summer approaches
这使得寻找猎物 and that makes the job of finding prey
相对容易 considerably easier.
北极兔 Arctic hares.
和北极狼一样 皮毛在短暂的夏天变白 Like the wolves, they stay white throughout the short summer.
奔跑之时 它们无处躲藏 While they can run, they can't hide.
更糟糕的是 现在是繁殖季节 And to make matters worse, now is the time they have their young.
母兔仅仅给幼兔喂食几分钟 A mother hare risks feeding her leverets
就要冒巨大的风险 for only a few minutes each day.
它的白色皮毛使其容易暴露 Her white colour makes her only too conspicuous.
当北极狼盯上它 它就会逃跑 When wolves are spotted, Mum runs for it.
这样很有效 幼兔不在它身边就更安全 That makes sense. Her leverets have a better chance without her.
与母亲不同 幼兔的伪装更好 Unlike their mother, the leverets are camouflaged.
即使在正上方 它们也几乎无法被发现 They're nearly impossible to spot, even when right upon them.
它们必须做的就是 What they must do
保持警惕 is keep their nerve.
必须要逃命时 When forced to break,
它们仍然会让北极狼劳累一番 they can still give the wolves a run for their money.
捕猎幼兔看似是一场不公平的竞赛 The leveret hunt may appear an unfair contest.
有一只被捉 就有一百多只逃过一劫 But for every one caught, hundreds more remain hidden.
在极北之地 寻找食物极为困难 Food is so hard to find this far north
狼群必须搜寻几百平方英里的土地 that a wolf pack must search hundreds of square miles
才能找到足够的食物 if it's to be successful
才能养育下一代 and success means raising the next generation.
要达到目标 狼群需要通力合作 To do that here, the wolves must work together.
所以 幼狼不仅由父母养大 So, the young are raised not only by their parents,
也依靠其他父辈的亲属 but by their aunts and uncles as well.
它们一起努力 保证幼狼长到接近成年的体格 Together, they try to ensure that each pup reaches near-adult size
以面对即将到来的冬雪 before the snow returns.
几只小野兔无法满足成长的幼狼 A growing pup needs more than just a few leverets.
狼群需要更大的猎物 The wolves need bigger prey
要捕捉猎物 and, to catch that
它们必须群体行动 they must hunt as a pack.
成年野兔很容易发现 Adult hares may be easy to spot,
但极难捕获 but they are far from easy to catch.
它们奔跑时速达40英里 They run at 40mph.
为捕获猎物 众狼团队协作 To catch one, the wolves work as a team.
一头狼靠得足够近希望咬到野兔的尾部 One of them gets close enough to bite the hare's tail
但野兔能在一瞬间改变方向 but a hare can change direction in an instant.
如果野兔能够向侧面躲避急转弯 If it can continue to sidestep and jink,
最终有可能会逃脱 it may ultimately outlast them.
最后 野兔逃掉了 Finally, it gets away.
群狼一起追击下一只野兔 For the next hare, the whole pack gives chase.
现在 狼多力量大 Now, numbers count.
领头狼保持步伐 The lead wolves keep up the pace.
其他狼在两侧跑 野兔无法改变方向 Others run on either side, so the hare can't change direction.
只够一群狼塞牙缝 A tiny meal for the whole pack
但只有一只野兔 but the only one there is.
到了七月 北极熊没有多少时间了 By July, time is running out for the polar bear.
三百万平方英里的冰面崩解飘离 Three million square miles of ice are fractured and adrift.
现在更难找到海豹 The seals are now much harder to find.
海豹分散在移动迷宫里 Scattered within an ever-shifting maze
北极熊优势全无 the advantage has swung away from the bear.
随着冰层断裂 北极熊甚至无法靠近海豹 With the ice now broken up, the bear can't even get close.
它靠近海豹时无法保持隐秘无声 She's too visible and noisy in her approach.
它别无选择 只能改变策略 She has no choice but to change her tactics.
在飘浮的冰层间游动 She swims amongst the drift ice
并且保持低调 and keeps a low profile.
一旦海豹下水 根本无法捉到 Once the seal is in the water, it's as good as lost.
北极熊必须在海豹入水前抓到它 She has to grab it before it hits the water.
一点小小的失误 The margin for error is tiny
就会酿成大错 and the cost can be great.
每一次失败使它愈加濒临饿死的危险 Each failed attempt brings her closer to starvation.
每年这个时候 北极熊的平均捕猎成功率 At this time of year, polar bears, on average,
只有二十分之一 succeed only once in 20 hunts.
如果捕猎者像这样瘦弱不堪 可能成功率会更低 If the hunter is skinny, like this one, that may not be often enough.
它只能继续尝试 All she can do is keep trying.
为防止气味泄露踪迹 To prevent her scent betraying her,
它绕了个大圈从下风头接近海豹 she makes a wide sweep to get downwind of the seal.
愈来愈近了 Getting close.
它就在海豹背后 She's now right behind the seal.
难以置信的是 它在水下捉到了海豹 Incredibly, she caught the seal underwater.
海豹个头不大 即便如此 It's only small, but even so,
仅仅其脂肪就含有10万卡路里的热量 its blubber alone will contain 100,000 calories
足够维持北极熊一周的生存 enough to sustain this bear for a week.
在此期间 它可能再捉一只海豹 And, in that time, she might even catch another.
但这种情况不会永远持续 But this can't go on forever.
随着夏天临近 气温逐渐升高 As summer continues, temperatures are rising.
每次捕猎都要耗费更多的体力 Each hunt requires more energy,
北极熊的储能逐渐耗尽 draining the bears of their reserves.
当海冰全部融化 When the melt is finally complete,
显露出最富饶的海域 it reveals some of the ocean's richest waters.
生命繁盛起来 There is an explosion of life.
数以百万的鸟类从南方赶来 Millions of birds arrive from the south.
在24小时不间断的白天 它们能不停进食 In the 24-hour daylight, they can feed around the clock.
北极海岸边突然遍布繁殖的鸟类 The Arctic coasts are suddenly thronged by breeding birds.
机会之窗向第三种捕猎者敞开 The window of opportunity has now opened for a third hunter
北极狐 the Arctic fox.
经过了一冬的蛰伏 北极狐终于能捕猎了 After a winter spent scavenging, the foxes can now finally hunt.
现在是养育幼崽的最佳时节 It's the best time to have pups.
20只幼崽需要在90天里养大到独立生活 Up to 20 of them will be raised to independence in just 90 days.
除非父母亲充分利用短暂的夏季 But none of them will survive their first year,
否则它们无法活过第一年 unless their parents make the most of the short summer.
随着冰雪融尽 北极狐退去白色皮毛 With the snow gone, the foxes shed their white fur
披上一身伪装的褐色 and become a camouflaging brown.
使捕猎更加容易 It makes hunting easier.
但一些鸟类有非凡的方法应对北极狐 But some birds have a dramatic answer to the fox problem.
这里没有树木 它们将巢筑在海边的崖壁上 There are no trees, so they make their nests high on sea cliffs,
北极狐根本够不着 well out of the reach of a fox.
然而大部分鸟类被迫将巢筑在地面 The vast majority, however, are forced to nest on the ground.
很多鸟巢依靠伪装 Many of them rely on camouflage.
绒鸭减慢心跳 有助于避免被发现 Eider ducks slow their heart beats, which helps them avoid detection.
其它鸟类不需要藏起来 Others have no need to stay out of sight.
强有力的北极贼鸥保护鸟蛋的方法是攻击 The powerful Arctic skuas defend their eggs with aggression
还有肮脏的伎俩 and dirty tricks!
北极狐还有别的选择 There are other options for the fox.
每年 多达3000万只海雀来到北极 Each year, upwards of 30 million little auks come to the Arctic.
它们在悬崖下的碎石坡上筑巢 They nest in the scree slopes at the base of the cliffs.
它们应对北极狐的办法是藏在乱石块下 Their answer to the fox problem is to hide deep among the boulders.
看起来很有效 And it seems to work.
饥饿的北极狐气急败坏 A hungry fox can get very frustrated.
追捕海雀可不是办法 Running at the auks is not the answer.
它得更加耐心才行 He needs to be more patient.
是时候使用狐狸著名的诡计了 It's time to use that famous foxy cunning.
如果乱石块藏得下海雀 也能藏得下狐狸 If the boulders can hide the auks, they can also hide a fox.
乱石块中隐藏着一个小脑袋 A tiny head, in among the boulders.
海雀快得无法捕捉 The auks are just too quick off the mark.
需要另一种动物分散注意力 What is needed is a distraction of some kind.
北极鸥也捕猎海雀 A glaucous gull, also hunting auks.
海雀能应付一种危险 那么两种呢 Little auks may cope with one threat, but what about two?
海雀不敌狐狸的诡计 The auks are out-foxed
狐狸幼崽能饱餐一顿了 and the pups will get their supper.
夏季仅剩下几周了 It's now the final weeks of summer.
海冰已经完全融化 The sea ice has completely gone.
整个冬天都漫游在冰冻海洋上的北极熊 The bears that wandered freely over the frozen ocean all winter
现在受困于海滩 are now marooned on beaches.
海豹正在海上捕鱼 The seals are fishing out at sea.
只有海象与北极熊待在岸边 Only walrus join the bears on the shore.
成年海象体型巨大 But adult walrus are gigantic.
它们重达2吨 还有长牙为武器 They weigh two tonnes and, armed with long tusks,
北极熊攻击它们过于危险 they're too dangerous for bears to take on.
在无冰的几个月里 北极熊的身体机能几乎停息 During these ice-free months, the bears' bodies almost shut down.
它们如同行尸走肉 They are zombie bears
怒不可遏 饥肠辘辘 overheated, hungry
急切期盼海冰回归 pining for the ice to return.
有些北极熊却不愿意躺着度过夏天 But some bears refuse to take the summer lying down.
这头熊现在的行为非同一般 This bear is doing something really extraordinary.
难以想象 还有什么地方比遍布碎石的海边悬崖 It's hard to imagine a place less suited to a polar bear
更加不适合北极熊 than 300 metres up on a crumbling sea cliff.
数以千计的海鸠在此筑巢 Guillemots nest here in their thousands,
正因这里对陆生掠食者十分危险 precisely because it's so dangerous for land-living predators.
对一只在夏末饥肠辘辘的北极熊而言 But the sounds and scents of a bird cliff can be irresistible
遍布海鸟的悬崖无法抗拒 to a starving bear at the end of summer.
绝望使北极熊冒着生命危险 Desperation has led him to risk his life.
唯一的奖励就是一些鸟蛋和幼鸟 The only prize to be had - a few eggs and chicks.
这是一场极端赌注 It is an extreme gamble.
它的方法很有效 He works methodically,
搜刮每一个够得着的鸟巢 scooping up the contents of every nest he can reach.
北极熊缓慢小心地移动 The bear moves slowly and carefully.
它就住在猎物周围 He lives and sleeps amongst his prey.
海鸠们无法阻止这场残杀 The guillemots can't prevent the carnage.
然而 有些海鸠却十分勇敢 Nonetheless, some bravely try to do so.
北极熊会在悬崖上待到夏天结束 The polar bear will remain on the cliff until the end of summer,
知道海鸠离开 when the guillemots will leave.
到那时 And, at that moment,
北极狐就会抓住时机 a fox will take his chance.
在遥远的内陆 狼群面临困境 Far inland, the wolves have a problem.
成年野兔已经四处分散 The adult hares have dispersed
幼兔们变得有组织起来 and the leverets have got organised.
其成熟的皮毛变成白色以应对寒冬 Their adult coat of fur has turned white for the winter,
用不着东躲西藏了 so they can no longer hide.
相反 它们聚在一起 Instead, they gather together.
看起来 狼群的捕食策略 The wolves' hunting technique, it seems,
无法应对这样一群猎物 can't deal with groups like this.
狼群放弃了野兔 They now leave the hares
转而寻找更危险的猎物 and instead go in search of a much more dangerous prey.
领地内最大的动物 The largest animal in their territory.
麝牛 Musk oxen.
一头麝牛体重超过一群狼的总和 A single bull weighs more than the entire wolf pack put together.
拥有坚硬的头骨 并且长着犄角 It has a reinforced skull, armed with horns.
牛群中也有小牛 There are also calves in the herd,
但受到良好的保护 but they are well-protected.
领头雌狼领导捕猎行动 The alpha female leads the hunt.
首先 它们正直冲向牛群 First, they run directly at the herd.
使牛群惊慌失措 The aim is to panic them.
溃散的牛群可能将小牛丢在后面 A stampeding herd might leave a calf behind.
狼群的策略开始奏效 The tactic begins to work.
但牛群重新集合 But then, the herd regains control.
它们围在小牛四周与狼群抗衡 They stand defiantly in a protective ring around the calves.
无法攻进去 There is no way in.
领头雌狼取消了捕猎 The alpha female calls off the hunt.
但还得继续寻找食物 But the search for food must go on.
为了在冬天赢得生存的机会 To stand a chance of surviving the winter,
狼群需要足够的食物 即使要冒生命危险 the pack needs to feed well now, even if it puts their lives at risk.
一头公牛 最危险的猎物 A lone bull - the most dangerous prey of all.
牛角的一次攻击足以对狼致命 One blow from his horns could kill a wolf.
但是众狼为了食物甘愿冒一切风险 But the wolves are now ready to risk everything for a meal.
公牛的体格能够轻易和狼群抗衡 The bull is easily their match, physically
众狼轮流进攻以耗尽公牛的体力 but the wolves take it in turns to wear him down,
它们正冒着生命危险 risking their lives to do so.
公牛被困在水沟里无处可逃 Trapped in the gully, the bull has nowhere to go.
尽管十分危险 但狼群持续进攻 Despite the danger, the wolves keep up their attack.
战胜这头公牛可能需要数小时 The bull may take hours to defeat
但这次捕猎足以供应整群狼一周的食物 but this kill will feed the whole wolf pack for a week.
随着好日子将尽 With the good times soon to end,
狼崽们完全要靠此生存 the lives of their pups may depend on it.
海岸的夏天在最后的盛况中结束了 Summer on the coast comes to an end with one last spectacle.
数十万海鸠幼鸟 Hundreds of thousands of guillemot chicks
正准备登上最后的舞台 are in the final stages of their preparations.
它们即将面对生命中最重要的一天 Ahead is the biggest day of their lives.
这一天它们跳下悬崖 离开巢穴 The day they will leave their nest by jumping from the cliffs
并且第一次尝试伸展羽翼 and try out their wings for the very first time.
这是一次飞行测试 It's quite a test flight.
安全的海面就在半英里外 Half a mile to the safety of the sea.
时机到了 在父亲的鼓励下 When the time comes, encouraged by their fathers,
第一只幼鸟纵身一跃 the first take the leap.
幼鸟的翅膀还很小 很僵硬 The chicks have tiny, stiff wings,
只比滑行强不了多少 so they can do little more than glide.
父亲轻推幼鸟 使其保持良好的飞行路线 Their fathers try to nudge them, to keep them on a good flight path
使它们最终能一路飞到水面 one that will take them all the way to water.
最初几只成功后 天空中满是跳跃者 With the first few safely away, the sky begins to fill with jumpers.
一波又一波的幼鸟和亲鸟冲入海中 Wave after wave of chicks and their parents career down towards the sea.
没有一直幼鸟单独飞行 No chick takes this first flight alone.
仅仅几天之内 In just a few days,
整整一代数以千计的幼鸟 将从悬崖一跃而下 an entire generation - thousands of chicks - will take this leap.
伴随着好运气和有利风向 大多数幼鸟安全入水 With luck and a fair wind, the majority make it to the water.
然而 很多幼鸟半途坠地 But nonetheless, many fall short.
北极鸥飞快捡拾美餐 Glaucous gulls are quick to grab a meal.
海鸠幼鸟对北极鸥毫无防御力 A guillemot chick has no defence against gulls
除非父亲及时赶到 unless father can get back in time.
海鸠幼鸟继续如雨般落下 The chicks continue to rain down.
那些和父母分离的幼鸟机会渺茫 Those that get separated from their parents stand little chance.
即使有父亲保护也无能为力 And even a father's protection may not be enough.
这是对北极狐的天赐良机 This is the fox's moment
一年中最容易的猎物 the easiest hunt of the year
但时间也是最短暂的 but it's also the briefest.
幼鸟们一次全出来了 The chicks all come at once.
幼鸟跳跃的同步性让狐狸劳苦不堪 The synchronisation of the jump overwhelms the fox.
运气不好的幼鸟使其它幼鸟得以存活 The bad luck of some allows the escape of others.
喂养北极狐全家的最后机会几乎在开始前 The last chance to fill his family's bellies is gone,
就已经消失了 almost before it started.
成功到达水面的幼鸟来不及休息 The chicks that have made it to the water have no time to rest.
由于无法飞行 它们必须向南游100英里 Unable to take to the air, they must swim 100 miles south
以躲避封冻的海面 before the ocean surface turns to ice.
冬天很快就要来了 Winter is approaching fast.
海冰正逐渐成型 The sea ice is starting to form.
漂浮的大陆即将呈现 A floating continent is about to materialise.
大地再次变成白色 The land becomes white once more
北极狐也是 as does the fox.
它未来几个月都要寻找食物 For it, months of scavenging lie ahead.
对北极熊来说 好日子终于回归 But for the bears, the good times have finally returned.
机会之窗再次到来 Their window of opportunity is back.