七 个 世 界 一 个 星 球
在我们的蓝色星球上 One continent on our planet changes
有一片最为变幻莫测的大陆 more dramatically than any other.
北美洲 North America.
整个大陆的景观在短短几分钟内就能变得风格迥异 Whole landscapes here can be transformed in a matter of minutes.
所有生命必须把握好时机 And all life has to be ready to seize the moment.
稍有差错就会有灾难性后果 Getting it wrong can be disastrous.
如果时机正确 就会有丰硕的回报 But time it correctly, and there can be great rewards.
北 美 洲
这是一片充满机遇的大陆 This is a land of opportunity.
北美洲的面积是英国国土面积的100多倍 Over 100 times the size of Great Britain,
解说：大卫·爱登堡
从赤道以北一直延伸到了北极地区 North America stretches from just above the equator almost to the North Pole.
气温幅度能从50摄氏度一路降至零下40度 Temperatures can range from 50 degrees Celsius to minus 40.
北美洲的极寒之地就是位于北极的北部地区 The coldest wilderness of all lies in the Arctic north.
这里是加拿大的育空地区 冬季的环境严酷无情 Here, in Canada's Yukon Territory, winter is brutal.
许多动物已经被迫向南迁徙 以躲避刺骨的严寒 Many animals have travelled south to avoid the worst of the cold.
对那些留下的动物来说 For those which stay behind,
生活变得举步维艰 life becomes very hard indeed.
一只加拿大猞猁出现了 A Canadian lynx.
没有什么猫科动物 No other kind of cat, anywhere,
比加拿大猞猁生活得更往北了 lives farther north than this one.
它们经常要长途跋涉数百公里外出觅食 The search for food could take him hundreds of miles.
一只白靴兔 A snowshoe hare.
这或许是个机会 This could be a chance.
它已经失去了突袭的良机 He's lost the element of surprise.
现在要想攻击猎物 它必须穿过纵横交错的树枝 And now there's a tangle of branches between him and his prey.
又错过了 Missed again.
加拿大猞猁消耗了过多体能 More of his energy wasted.
它发现了另一只白靴兔 Another hare...
这次是在开阔地带 ...this time out in the open.
可惜它再次失手 And another failure.
如果不能尽快捕获猎物 它可能无法熬过漫漫寒冬 If he doesn't kill soon, he may not survive these winter months.
但是在北美洲 But in North America,
变化会相伴左右 change is never far away.
当4月来临 数十亿吨的冰雪开始消融 April - and billions of tonnes of snow and ice are starting to melt,
给当地动物带来了新的机会 bringing new opportunities.
大部分冰雪融水一路向南流淌 Much of the water drains southwards.
上万条小溪汇聚在一起 形成了北美洲最大的河流系统 10,000 creeks join, forming North America's biggest river system.
这些冰雪融水沿着密西西比河穿越北美洲的心脏 The meltwaters travel 2,000 miles down the Mississippi,
一路蜿蜒流淌3000多公里 right through the heart of North America.
在田纳西州的溪流中 小须美鱥即将繁殖后代 In the streams of Tennessee, river chub are getting ready to breed.
这只雄鱼正忙着堆砌石块 This male is busy building a mound of stones, in which,
如果运气够好 它能引来雌鱼在石堆产卵 if he's lucky, a female will lay her eggs.
水流越湍急 它们的工作难度就越大 As the river flows faster, the work gets harder.
这是不错的开始 但同性之间的竞争异常激烈 It's a good start, but rivals are doing the same thing
其它雄鱼对它的石块虎视眈眈 and want some of his pebbles.
入侵者遭到驱逐 The intruder seen off,
它可以继续安心工作了 and it's back to business.
最后再稍加装饰一下 A few finishing touches.
终于 这座耗用7000多块石头堆砌而成的巢穴 And then, with the last of some 7,000 stones,
顺利建成了 his nest is complete.
时间刚刚好 一只雌鱼翩然而至 And right on time, here is a female.
不过石头豪宅还差最后的点睛之笔 But the mound now needs one last feature.
一道方便雌鱼产卵的小沟 A trench where she can lay her eggs.
雄鱼轻轻晃动身体 将雌鱼推到了合适的位置 And with a gentle shimmy of his body, he nudges her into position.
它选择的产卵地点 And she deposits her eggs
必须要远离洋流和捕食者的威胁 where they will be safe from both currents and predators.
雄鱼已经完成使命 His work is done.
受精卵将会孵化 The eggs will hatch,
它孵化建造的巢穴在洋流侵蚀在洋流侵蚀 and then his mound will be slowly dismantled
会渐渐土崩瓦解 by the current.
所以来年 它只能重新建造 So next year, he'll have to start all over again.
现在 春季的号角即将吹响 Spring is now well on its way.
不可思议的是 北美洲的野花比比皆是 North America is wonderfully rich in wild flowers.
野花种类高达10000多种 There are over 10,000 species of them.
蜂鸟从南方飞来 享受这场甜美的花蜜盛宴 Hummingbirds fly up from the south to feast on the nectar.
北美洲的海岸沿线拥有世界上最大的潮汐 Along the North American coast, the tides are the largest in the world.
支离破碎的海岸线迫使海水涌向狭长的水湾 The fragmented shoreline forces seawater to rush up narrow inlets.
每次随着潮水退去 海鲜储藏室的大门就会全面敞开 And each time the tide retreats, it opens a freshly stocked larder.
短短两小时之内 这片18000多平方公里的 7,000 square miles of extra coastline
额外海岸线就赫然呈现在眼前 is uncovered in the space of just two hours.
一头美洲黑熊妈妈正四处寻找适合幼崽食用的东西 A mother black bear is looking for something suitable for her cubs.
这是它们第一次来到海边 This is their first ever trip to the seaside.
几个小时后 潮水将会再次上涨 In a few hours, the tide will return.
它们必须跟紧妈妈 So they must keep up with Mum.
这是美味快餐 Here's something tasty -
螃蟹 crabs.
大螃蟹的长钳应付起来很麻烦 Big crabs can give a nasty nip.
所以它们最好还是从小螃蟹开始 So it's best to start off with smaller ones.
在春季 美洲黑熊有四分之三的食物都来自海滩地带 During spring, three quarters of the bears' food comes from the beach.
但是现在 海滩上不只有它们 But now...this family is not alone.
一只成年雄性 An adult male.
个头是这只黑熊妈妈的两倍 这一家三口闯入了它的地盘 He's double her size, and they're in his territory.
幼崽们很清楚那叫声的含义 The cubs know that call.
现在还是走为上策 It's time to head for safety.
熊类的视觉很差 但嗅觉异常敏锐 Bears have poor eyesight, but their sense of smell is acute,
这头雄性黑熊已经发现了外来闯入者 and the male has detected intruders.
它很清楚幼崽们躲藏的位置 He knows exactly which tree they are in.
幼崽们待在树上倒是很安全 If the cubs stay up there, they'll be safe,
但也因此丧失了宝贵的觅食时间 but they're losing precious feeding time.
雄性黑熊留下气味标记后扬长而去 For now, he's content to leave his scent mark.
这是对侵入者明显的警告 A warning note for trespassers.
母子三个继续前进 The family moves on.
幼崽们今天的午餐看来只能带回去吃了 For the cubs, lunch today will have to be a takeaway.
潮水开始迅速上涨 The tide comes in.
短短几分钟内 海滩化为汪洋 一天的觅食时间结束 And within minutes, feeding time is over for another day.
北美洲天气变暖时 As the continent warms,
在几个冷暖适宜的 on a few special nights,
特殊夜晚 when the temperature is just right...
北美洲的森林地带开始上演一场令人眼花缭乱的荧光大秀 ...the forests of North America put on a show.
雄性萤火虫纷纷飞向天空 Male fireflies are taking to the air.
这些昆虫其实并非蝇类 而是一种甲虫 These insects are not, in fact, flies, they're a kind of beetle.
雄性萤火虫能够产生世界上最节能的亮光 The light produced by the males is the most energy-efficient on Earth.
有些种类的萤火虫能够一致发出亮光 Some species synchronise their flashes
由此昭告它们的信息 to increase the visibility of the message.
如果一只雌性萤火虫看到自己喜欢的信息 If a female sees something she likes,
它会做出回应 she returns the signal.
看来消息起作用了 It looks as if the message is working.
但是森林里危机四伏 But the forest is booby-trapped...
狡猾的圆蛛布下了重重陷阱 ...by orb-weaver spiders.
萤火虫即便死了 也会继续发光 The firefly continues to glow, even in death.
其它雄性只看到闪光 却丝毫没察觉到危险 Other males see the flashes, but not the dangers.
这只蜘蛛的储藏室即将满满当当 The spider's larder is filling up.
可是有一只萤火虫落网 But for every firefly that gets caught,
同时也有成千上万只避开了陷阱 thousands avoid the traps.
这只雄性萤火虫很幸运 And this male is lucky.
它已经找到了伴侣 He's found a mate.
在漫漫长夜 And over the course of the night,
数百万只萤火虫会找到配偶 millions will pair up.
北美洲共有150多种不同的萤火虫 There are over 150 different species of fireflies in North America,
而且每种萤火虫都有自己独特的闪光密码 and each has its own flash code.
一旦完成交配 雌性萤火虫将在地下产卵 Once they're mated, the females deposit their eggs in the ground.
对那些没有找到伴侣的 And for those that didn't find a mate,
它们的机会早已随风而逝 their one chance has come and gone.
北美洲大陆的腹地几乎滴雨未下 Little rain reaches the heart of the continent.
将近250万平方公里的广阔土地上 几乎看不到一棵树木 For over a million square miles, there's not a tree in sight.
许多当地动物大多数时间都生活在地下 Many of those living here spend much of their time underground.
草原犬鼠 就像体形稍大的穴居松鼠 A prairie dog - a kind of large, burrowing squirrel.
哨兵们严阵以待 随时准备向同伴发出警告 Sentinels keep watch, ready to warn others of any danger.
每年这个时节 它们要保护新一代幼崽 And at this time of year is a new generation to protect.
这只草原犬鼠妈妈养育了6只幼崽 This mother has six pups.
年轻幼崽不停地索取更多食物 The youngsters constantly beg for food.
毕竟这些幼崽并不擅长分享 After all, the pups aren't great at sharing.
但这里不只是草原犬鼠的天下 But the prairie dogs don't have the prairies to themselves.
一只美洲獾 An American badger.
这些初出茅庐的幼崽从没见过美洲獾 The pups have never seen one before.
但美洲獾会对它们痛下杀手 And badgers eat pups.
一只穴小鸮 A burrowing owl.
它非常清楚美洲獾的致命威胁 It also knows that badgers are dangerous.
穴小鸮同样也有幼鸟 自然不希望美洲獾靠近它们 It too has young and does not want the badger anywhere near them.
美洲獾无奈只能放弃 Eventually, the badger gives up.
它决定到其它地方碰碰运气 He sets off to look elsewhere.
如果能找到一片高草丛来隐藏身形 If he can find a place where the grass is higher than he is,
它捕猎成功的几率会大大提高 he will have a better chance.
草原犬鼠妈妈发出警报 The mother sounds the alarm.
成年草原犬鼠对危险了如指掌 Adults know the danger all too well.
4只幼崽顺利躲入安全的地下洞穴 Four pups make it to safety below.
它们的母亲也不敢在地面停留太久 But their mother dare not wait above ground any longer.
草原犬鼠的幼崽有大约一半都无法活到成年 Half of all prairie dog pups don't survive to adulthood.
对这些草原居民来说 它们面临的 Predators are not the only problem faced by animals
不只是捕食者的问题 living on these great plains.
来自墨西哥湾的温暖气流一路向北 穿越开阔的大草原 Warm air sweeps up from the Gulf of Mexico and across the open prairies.
到了这里 因为没有高山遮挡 And here, with no mountains to block it,
它与来自北极的寒冷气流正面遭遇 it meets the frigid air from the Arctic.
结果令人叹为观止 The results are spectacular.
两股气流混合旋转 As the air currents mix and swirl,
最后形成最可怕的自然力量之一 they build into one of nature's most fearsome forces.
那就是龙卷风 Tornados.
这些龙卷风的旋转时速高达将近500公里 These twisters spin at speeds of up to 300mph,
是世界上速度最快的风 the world's fastest wind.
这里每年会遭遇1000多次龙卷风袭击 Over 1,000 tornadoes touch down here every year.
落基山脉犹如一道屏障 These drenching summer storms
阻止了这些浸满水汽的夏季风暴进一步向西蔓延 are prevented from spreading westwards by the Rocky Mountains.
有些山峰的海拔高达4000米以上 Some peaks are over four kilometres high,
因此在群山西侧 大多数土地仍旧一片干涸 so, beyond them, to the west, much of the land remains parched.
这片广阔无垠的美洲荒漠占地大约250多万平方公里 The great American deserts cover over a million square miles.
在这里 岩石在狂风烈日的长期侵蚀下 渐渐化为齑粉 Here, roasted by the sun and blasted by the wind, the rocks disintegrate,
昔日巍峨的山脉一点点土崩瓦解 变为漫漫黄沙 and mountains, particle by particle, are reduced to sand.
这里曾是恐龙游荡的高原地带 如今就只剩下这些柱状物 These pillars are all that remain of a plateau where dinosaurs once roamed.
能在这里生存的动物寥寥无几 Few animals can now survive here.
就像所有荒漠一样 当地动物 In summer, as in all deserts,
在夏季的天敌就是炎热 the enemy is heat,
而且它每日都在肆虐 and it returns every day.
早上七点 At seven in the morning
这里的气温已经达到25摄氏度 the temperature is already 25 degrees Celsius.
对一个特殊的恐龙后裔来说 The clock is ticking
它必须分秒必争 for one unusual descendant of the dinosaurs.
它就是走鹃 A roadrunner.
一种北美洲荒漠地带特有的鸟类 Found only in the deserts of North America.
它生来就适合在地面活动 Built for a life on the ground.
走鹃的奔跑时速能超过30公里 - He can run at over 20mph. - (WARBLES)
但它要捕食的猎物领先了一步 But the prey he seeks are one step ahead.
走鹃要面临的挑战是选择正确的目标 The roadrunner's challenge is picking the right target.
一只钝尾毒蜥 A Gila monster -
个头太大了 too big.
烈日悬于半空 气温飙升至40摄氏度 By mid-morning, it will be 40 degrees Celsius.
就连体型最小的蜥蜴也到阴凉处寻求庇护 Even the smallest lizards will soon head for cover.
一只蜈蚣 A centipede.
折腾一上午 这点收获实在少得可怜 Slim pickings for a morning's work.
当热浪渐渐消退 Hunting should get easier
猎物在外逗留的时间更长 and prey will stay out longer
捕猎应该会容易些 once the summer's peak begins to fade.
在北美洲东海岸 夏季即将结束 On the East Coast, summer is coming to an end.
寒流席卷整个佛罗里达海岸 Cold currents are sweeping along the coast of Florida.
伴随寒流而来的还有鲻鱼 它们正一路迁徙 And with them come grey mullet on their migration
前往南部的产卵地 to their spawning grounds in the south.
数百万的鲻鱼 Millions of them -
紧紧聚集在一起 它们像浮油一样笼罩整个水面 and packed so tightly, they stain the water like an oil slick.
海滩上几乎没人注意到它们 Few people on the beach are even aware of them.
鲻鱼选择尽可能地靠近海岸 The mullet keep as close to the shore as possible,
因为深水中有许多捕食者 for, in deeper water, there are predators.
这些鲻鱼邻近海滩 Close to the beach,
必须避开人类的游泳者 they have to keep clear of human swimmers.
但是现在 来自外海的捕食者已经发现它们 But now hunters from the open ocean have detected them.
大海鲢体长超过两米 体重超过100公斤 Tarpon - over two metres long and weighing over 100 kilograms.
为了靠近浅水处的鲻鱼 To get close to the mullet in the shallows,
大海鲢侧身逼近 the tarpon turn on their sides.
现在鲻鱼看不到它们闪闪发光的银色侧面 Now the mullet can't see their shining silver flanks
直到为时已晚 until it's too late.
盛宴开始 And feasting begins.
黑边鳍真鲨闻风而来 Black-tipped shark arrive.
鹈鹕也加入捕猎大军 Pelicans join in.
但是这些攻击对庞大的鱼群来说 几乎毫无影响 But these attacks have little effect on the immense shoals.
鲻鱼的数量是敌人的10000倍 The mullet outnumber their enemies by 10,000 to one.
庞大的鱼群仍旧浩浩荡荡地涌向北大西洋 So the great procession travels on, into the Northern Atlantic Ocean,
在那里 它们最终安顿下来产卵 where, at last, they will be able to spawn in safety.
北美洲迎来了秋季 Autumn arrives in North America.
北美洲几乎没有从东向西横跨大陆的山脉 No mountain range spans the continent from east to west,
所以来自北极的冷空气一路势不可挡地南下 so there is nothing to stop cold air from the Arctic
最远可以到达路易斯安那州 sweeping down unhindered as far south as Louisiana.
秋季给南方沼泽披上了色彩 Autumn brings colour to the southern swamps.
这里一年中大部分时间都闷热无比 Here, it has been hot and humid for most of the year,
现在气温跌至零下 这对当地居民来说 and now these sub-zero temperatures are something of a trial
是严峻的考验 for the local inhabitants.
一条美国短吻鳄 An American alligator.
为了应对低温 美国短吻鳄将心率 The alligator reacts to the chill by slowing its heart rate
降到了每分钟一下 to barely one beat per minute.
这种冬眠方式能节省身体能量 It's a kind of energy-saving winter sleep.
其它动物就没有这个本领了 But other creatures don't have this ability.
沼泽中体形最大的动物居民 The largest inhabitants of the swamp.
而且是大象的亲戚 A relative of the elephant.
它就是海牛 A manatee.
一头雌性海牛通过鳍状肢后面的乳头为幼崽喂奶 A female provides milk for her calf from a teat behind her flipper.
它或许能够经受住严寒 She might be able to survive the chill.
但它的幼崽不行 But her calf cannot.
所以每到秋季 它们必须寻找更加温暖的水域 So every autumn, they need to find warmer waters.
等待它们的是漫长的旅程 They have a long journey ahead -
这可能意味着数百公里的长途跋涉 it could be hundreds of miles.
而且它并非孤身一个 And she is not alone.
它们赖以求生的温暖水域来自一个不同寻常的源头 The warm waters they need to survive come from an unusual source.
一条巨大的地下河 An immense underground river
流经佛罗里达岩石密布的地下通道 flows through subterranean channels in Florida's rocks.
它在某些地方涌出地表 创造出1000多个喷泉 In places, it comes to the surface, creating over 1,000 springs.
现在正值冬季 Now, in winter,
这些山泉的温度比周围水域要高上10度左右 these springs are ten degrees warmer than the surrounding waters.
所以海牛从四面八方蜂拥而来 So manatees come here every year from far and wide.
在这里 它们可以放松休息 And here they can relax.
可以清洁后背 They can get their backs scrubbed.
还可以相互交流 And they socialise.
所有海牛显得悠然自得 No-one is in much of a hurry.
年轻海牛有可能遇到一些令人吃惊的邻居 And young manatees have a chance to meet some surprising neighbours.
在夏季 逗弄一条美国短吻鳄或许是自寻死路 In summer, playing with an alligator might be a dangerous game.
可是现在 But now, at any rate,
这些巨型爬行动物因为身体寒冷 对外界骚扰熟视无睹 the giant reptiles are still too chilled to react with any vigour.
没有这些温暖的池塘 Without these warm pools,
佛罗里达州的海牛几乎很少能熬过严冬 few of Florida's manatees would be able to survive the winter.
但是这些温暖水道同样深受人类的欢迎 But the waterways here are now very popular with people, too,
遭遇在所难免 许多海牛身上都留有船只螺旋桨造成的伤疤 and many manatees carry scars inflicted by the propellers of boats.
就连它的幼崽也已经挂彩 Her calf has already had its first scrape.
这里每年有100多头海牛由于人为因素丧生 Every year, more than 100 manatees die from human causes.
随着佛罗里达人口数量的增加 As the human population of Florida grows,
野生动物的压力与日俱增 so wildlife is coming under increasing pressure.
在北美洲各地 Across North America,
每10年就有大约40万公顷的荒野消失 a million acres of wilderness are lost every decade.
但是受到人类威胁最严重的 But it is in the far north of the continent
自然要数位于北美洲最北端的动物们 that human beings are affecting wildlife most critically.
加拿大气候变暖的速度远远超过世界上其它任何国家 Canada is warming faster than any other country on Earth.
北极熊长期以来一直依靠海冰捕猎 Polar bears have always relied on sea ice for their hunting.
可是现在夏季变得越来越长 越来越热 But summers are now getting longer and hotter.
多数北极熊 For most polar bears,
在夏季只能忍饥挨饿 this is a time of starvation.
在哈得孙湾海岸 On the shores of Hudson Bay,
一些北极熊正在寻找新的食物来源 some bears are finding a new source of food.
它们都在寻找同样的猎物 They're all looking for the same thing,
而且它们有各自的捕猎方式 and they have their own ways of catching it.
首先 它们必须找到合适的岩石 First, they must find the right rock.
接下来是严阵以待 Now they must wait.
潮水不断上涨 带来了其它北方巨兽 The tide comes in, bringing with it other northern giants.
它们就是白鲸 Beluga whales.
在近岸水域 Close to the shore,
白鲸的幼崽相对安全 能避开像虎鲸这种海洋捕食者的威胁 their calves should be safe from ocean-going predators such as orca.
这里已经聚集了3000多头白鲸 Over 3,000 whales have gathered here.
一头年轻雄性采取行动 A young male makes his move.
北极熊是经验丰富的海洋捕食者 Polar bears are skilled marine hunters...
而白鲸的游泳速度缓慢 ...and beluga are slow swimmers.
白鲸只要密切提防捕猎的北极熊 As long as a whale can keep an eye on a hunting bear,
就不会有危险 it should be safe.
这只年轻北极熊还在学习 This young bear is still learning.
经验更丰富的北极熊清楚捕猎要有耐心 More experienced bears know to be patient.
捕猎成功与否取决于瞬间的时机把握 Success will depend on split-second timing.
北极熊一口咬住白鲸的后脑部位 使其当场毙命 A bite at the back of the head, and the kill is swift.
据报告 只有北美洲这个偏远角落的北极熊 This extraordinary behaviour has only been reported here,
才出现这种特殊行为 in this remote corner of North America...
而且这只是近几年才出现 ...and only in the last few years.
这一小群北极熊找到了新颖独特的捕猎方法 This one small group of bears has found an ingenious way
能在食物匮乏的夏季存活下来 of surviving the lean summer months.
但是对其它北极熊来说 生存并不容易 But for others, it is not so easy.
人类继续改变着我们的星球 We continue to transform our planet,
四季变得越来越难以预测 and the seasons are becoming less predictable.
北美洲的野生动物能适应这些改变吗 Will the wildlife of North America be able to adapt?
不只在以变化闻名的北美洲 Not only on this continent, known for its change,
而是在快速变化的整个地球 but in a rapidly changing world?
下集预告 Next time...
一个野生动物展示地球上最宏大演出的大陆 ...the continent where wildlife puts on the greatest show on Earth.
非洲 Africa.