我们的星球（2019）

while the females' eggs complete their development.
‎但它们的麻烦还没结束
But their troubles are not yet over.
‎这些水域是美国 ‎唯一的淡水海豹的家园
These waters are the home of the only freshwater seals in America.
‎鲑鱼已经八周没有吃东西了
The salmon haven't eaten in eight weeks
‎但它们还是能比捕食者游得快
but they can still outswim these predators.
‎海豹们转变了策略
The seals switch strategy
‎开始在光天化日之下隐藏
and start to hide in plain sight.
‎这是非常少见的行为
In a rarely seen behavior
‎它们等待着鲑鱼来到自己身边
they wait for the salmon to come to them.
‎令人惊讶的是 ‎它们无视了眼前的雄性
Surprisingly, they ignore the males right in front of them.
‎而是去捕捉
And go for the females
‎孕育着高热量卵子的雌鱼
who are laden with calorie-rich eggs.
‎但是有一条鲑鱼被吃掉
But for every salmon that's taken
‎就有会有几千条安全通过
thousands get through.
‎在漫长的旅途中 它们遍体鳞伤
Battered and bruised from their long journey
‎最终到达了它们的产卵池
they have, at last, reached their spawning pools.
‎一旦来到这里 雄性和雌性会配对
Once here, males and females pair up
‎共同争取最好的巢址
and, together, fight for the best nest sites.
‎终于 它们交♥配♥了
Finally, they mate.
‎它们一生仅有这一次交♥配♥
It's the only time they will ever do so.
‎为了完成这次史诗般的迁徙 ‎它们已经付出了一切
They've given everything to complete this epic migration.
‎它们的生命结束了
Their lives are over.
‎它们腐烂的身体中的营养物质 ‎滋养着水域
The nutrients from their decaying bodies fertilize the water.
‎这样的牺牲 确保了下一代
A sacrifice that ensures the next generation
‎能够拥有最佳的起点
will have the very best start in life.
‎（北冰洋 斯堪的纳维亚）
‎北极高地的八月
August in the High Arctic.
‎经过三个月的连续日照
After three months of continuous daylight
‎海冰已经所剩无几
little is left of the sea ice.
‎这只北极熊和它八个月大的幼崽
And that makes life very hard for this ice bear
‎谋生变得越发艰难
and her eight-month-old cubs.
‎三个月前 它们在冰面上 ‎猎杀富含脂肪的海豹
Three months ago, they were hunting blubber-rich seals out on the ice.
‎现在 它们被迫连续数日游泳
Now they're forced to swim continuously for days on end
‎寻找它们能找到的任何食物
in search of whatever food they can find.
‎北极熊游泳消耗的能量比走路多五倍
Polar bears use five times more energy when swimming than walking.
‎这种情况 ‎开始对最小的幼崽造成影响了
And that is beginning to take its toll on her smallest cub.
‎它觉得很难跟上
He's finding it hard to keep up.
‎但它妈妈太饿了 不能等太久
But his mother is too hungry to wait for long.
‎它能闻到这座岛上有食物的味道
She can smell food somewhere on this island.
‎俯冲的海鸥表明它已经接近了
And the dive-bombing gulls are a sign that she's close.
‎对于地球上最大的陆地食肉动物来说
For the largest land carnivore on Earth
‎这些雏鸟还不够塞牙缝的
these chicks are not much of a meal.
‎不过对幼崽来说 ‎这是非常需要的助力…
Though they would be a much-needed boost for the cubs...
‎前提是它们能在食物消失前吃到
if they can get down to it before it's gone.
‎较弱的幼崽脚步不大稳健
The weaker cub is not very sure-footed.
‎等到它追上的时候 已经太迟了
By the time he's caught up, it's too late.
‎因为食物稀缺
With food so scarce
‎没有休息的时间
there is no time for rest.
‎爬上去应该很容易
The climb back up should be easy.
‎当然 它的同胞似乎很淡定
Certainly, his sibling seems to take it in his stride.
‎但长途游泳之后 ‎较弱的幼崽体力不足了
But after that long swim the weaker cub has little energy left.
‎由于无法跟上 它慌了
Unable to follow, he panics
‎走向了错误的方向
and heads in the wrong direction.
‎在这里滑倒 ‎就意味着跌落15米摔到下面的岩石上
A slip here would mean a 15-meter fall onto the rocks below.
‎它的妈妈没有注意到它的问题
His mother takes no notice of his problems
‎因为它急于找到另一餐
so desperate is she for another meal.
‎它的生存取决于是否能紧跟妈妈
His survival depends on staying close to his mother.
‎如果它跟不上 妈妈就不得不抛弃它
If he can't keep up, she will be forced to abandon him.
‎它成功了
He's made it.
‎只不过它发现必须继续前进
Only to find that he must still keep going.
‎这是一趟幼崽可能无法幸存的旅程
It's a journey this young cub may not survive.
‎由于夏季海冰融化的速度前所未有
With summer sea ice melting earlier than we've ever known
‎北极熊只能花费更多的时间用于游泳
polar bears are having to spend more of their year swimming.
‎对于习惯穿越冰面的动物来说
For animals used to traveling across ice
‎这些变化实在是太大了
these changes may well prove to be too great.
‎（九月）
‎在北极以南六千公里处
Six thousand kilometers south of the Arctic
‎夏季的太阳也在照射波斯湾的浅水区
the summer sun is also heating the shallow waters of the Persian Gulf
‎使这里的海水成为地球上最热的
making the sea here the hottest on the planet.
‎这吸引了海洋中最大的鱼
And that attracts the ocean's biggest fish.
‎鲸鲨
The whale shark.
‎在经历数千公里的旅程后
After a journey of thousands of kilometers
‎它及时赶上了 ‎一年中最棒的猎食活动…
it's arrived in time for one of the best feeding events of its year...
‎并且正在前往一个特定的地点
and is heading to a particular spot.
‎阿尔沙欣油田的水域
The waters of the Al Shaheen Oil Fields.
‎平台起着礁石的作用
The platforms act as reefs
‎为数百种生物提供家园
providing a home for hundreds of species.
‎每个钻井平台的半公里范围内 ‎不允许有任何船只
No vessels are allowed within half a kilometer of each rig
‎因此创造了海洋保护区 ‎使鱼类可以安全产卵
so creating marine sanctuaries where fish can spawn in safety.
‎金枪鱼也在其中
Tuna are among them.
‎它们只有在 ‎摄氏25度以上的水温中才会繁殖
They can only breed when the water is 25 degrees Celsius or more.
‎所以在夏天海湾最热的时候
So, in summer, when the gulf is at its hottest
‎它们聚集起来 产下数以百万计的卵
they gather together and release hundreds of millions of eggs.
‎水的表面因为产卵而变得浑浊
The water's surface becomes thick with spawn.
‎这就是鲸鲨越洋的目的
And that is what the whale shark has crossed oceans for.
‎它通过一米宽的嘴吸入海水
Taking in water through its meter-wide mouth
‎收集鱼卵
it collects the eggs.
‎更多的鲸鲨到来参加盛宴
More sharks arrive to join the feast.
‎但这是地球上最热的海洋
But this is the hottest sea on Earth.
‎每天早上进食几个小时后
And after feeding for a few hours each morning
‎鲸鲨必须返回更凉的深水处
the whale sharks will have to return to the cooler depths.
‎在产卵旺季时
At the height of the spawning season
‎每平方公里可能有超过一百只鲸鲨
there may be over 100 per square kilometer.
‎这是世界上最大的鲸鲨聚会之一
It's one of the largest gatherings of whale sharks on the planet.
‎更难能可贵的是 ‎这种场景在2010年才首次被记录下来
And all the more remarkable that it was only recorded for the first time in 2010.
‎（撒哈拉）
‎回到塞伦盖蒂平原上
Back in the Serengeti
‎一百万只牛羚和斑马仍然在迁徙
a million wildebeest and zebra are still on the move
‎跟随太阳和雨水 寻找新鲜的牧草
following the sun and rain in search of fresh grazing.
‎而在兽群之中
And in amongst the throng...
‎还有新生命
...new life.
‎这只斑马马驹和它的家人 ‎穿梭在牛羚群中 以求获得安全
This zebra foal and his family travel amongst the wildebeest for safety.
‎它才四周大
He is just four weeks old
‎跟上斑马群的速度是非常困难的
and keeping pace with the herd is a daily struggle.
‎但它最大的障碍就在眼前
Yet his biggest hurdle lies just ahead.
‎马拉河
The Mara River.
‎这里水流湍急
Its fast-flowing waters
‎每年都会夺走六千只动物的生命
claim the lives of 6,000 animals a year.
‎对从未游过泳的小马驹来说 ‎穿越河道将是重大考验
Crossing it will be a major trial for a foal that has never swum before.
‎兽群靠近河边
The herd nears the river's edge.
‎没有谁想第一个过河
None wants to be the first to cross.
‎但随着数量增多
But as numbers increase
‎兽群前排的压力越来越大
pressure mounts on those at the front.
‎一旦有一只下水
Once one commits
‎闸门就彻底打开了
the floodgates open.
‎但小马驹和它的家人在等待
But the foal and his family wait.
‎许多牛羚在挤压中被淹死
Many wildebeest drown in the crush.
‎斑马仍然在等待
Still, the zebra hold back.
‎这是有充分理由的
And with good reason.
‎五米长的尼罗河鳄鱼
Five-meter-long Nile crocodiles.
‎是非洲最大的鳄鱼之一
Amongst the biggest in Africa.
‎这些巨型爬行动物 ‎可能从去年开始就没有进食过了
These giant reptiles may not have eaten since this time last year.
‎有这么多目标可供选择
With so many targets from which to choose
‎它们可以慢慢来
they can afford to take their time.
‎也许很快
Soon, perhaps
‎鳄鱼就会吃饱了
the crocodiles will have taken their fill.
‎没有那么好运
No such luck.
‎斑马不能再等了
The zebra can wait no longer.
‎它们必须待在兽群里
They must stay with the herd.
‎所以小马驹现在 ‎必须为自己的生命而游泳了
So, the young foal must now swim for his life.