七个世界，一个星球（2019）

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,
画外音
大卫 · 爱登堡 爵士
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1♥0♥0♥0♥0♥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.