自然的运作（2012）

地球上有一千万个物种
10 million species live on planet earth.
但没有哪个物种 可以单独存活下来
But none can survive alone.
一切生命都有赖于 与其他物种的联♥系♥
All life depends on connections.
数百万种动植物间 有着始料未及的复杂联♥系♥
Unexpected and complex relationships between millions of plants and animals.
这次...
This time...
草原
grasslands.
这只猴子要靠长颈鹿生存下去
Where this monkey depends on the giraffe.
罕见的联♥系♥让一些 最奇特的动物繁衍生息下去
And bizarre connections allow some of the most extraordinary animals to thrive against all odds.
（大自然法则）
（草原）
草原占地球陆地面♥积♥的 四分之一
Grasslands cover a quarter of the land on earth.
北美大草原
The Prairies of North America.
亚洲大草原
The Steppes of Asia.
以及非洲大草原
And the savannah of Africa.
这里的生物 必须为了生存而搏斗
Life here must fight to survive.
母狮子必须吃足够量的肉 才能产奶喂食幼狮
The lioness must eat large amounts of meat to produce enough milk to feed her cubs.
奶水提供给它们 不可或缺的能量和维他命
This milk provides them with vital energy and vitamins.
但其中还含有另外一种 必要元素
But it also contains another essential ingredient.
蛋白质
Protein.
幼狮的成长离不开蛋白质
The cubs can't grow without it.
它们需要蛋白建构身体每一部分 新的肌肉、骨骼及毛发
They need protein to make every structure in their bodies, new muscle, bone, and hair.
它们的母亲需要蛋白质来 维持并修复身体组织
Their mother needs it to maintain and repair her tissues.
她从吃下的动物身上摄取蛋白质 而这些动物则从草中摄取蛋白质
She gets protein from the animals she consumes which in turn get it from the grass they eat.
制♥造♥这些蛋白质 需要一种必备的元素
Making these proteins requires an essential element.
氮
Nitrogen.
没有这一营养成分 生命几乎不可能存在
Without this nutrient, life would be impossible.
但草原极其缺少 这种重要的元素
But grasslands run critically short of this vital ingredient.
争夺氮的战争 在草原上更加激烈
And competition for nitrogen is more intense in grasslands
和任何其他陆地生态系统相比
than almost any other terrestrial ecosystem.
但是它们给养了地球上 一些最大型的生物
Yet they support some of the largest animals on the planet.
这些大型掠食动物 是如何在这里存活下去的
The story of how these top predators survive here
要从食物链的底层说起 就是草
starts at the bottom of the food chain with the grass itself.
草可能看上去很简单 但不容小觑
Grass may look simple but don't be deceived.
它是一种十分特殊的植物 能克服其他植物
It's a very special plant.
因自身结构原因 而无法耐受的氮缺少问题
It can cope with a nitrogen shortage that other plants simply can't tolerate because of its structure.
草根部能长到3米深 深钻入地下 收集所有能得到的氮化合物
Grass roots grow up to 3 metres long delving deep to gather up all the nitrogen compounds they can.
而草也能长出 含有少量氮成分的叶子
And grasses can produce leaves with little nitrogen.
这让其能活下去 为食物链的上一层提供食物
This allows it to survive, providing food for the next level,
即食草动物
the plant eaters.
单是非洲 就有数百万的食草动物
And Africa alone has millions of them.
但草本身并不含氮
But the grass itself doesn't contain much nitrogen,
因此食草动物面临着一项挑战
so grazing animals have a challenge,
要从草中挤出足够的氮来
to squeeze enough nitrogen out of the grass.
黑斑羚是非洲最常见的 羚羊之一 并且主要以草为食
Impala are one of Africa's commonest antelopes and eat mostly grass.
它们经由一种特殊策略 克服了食物营养含量低问题
They survive this nutrient poor diet with a special strategy.
她吞食草 方式和我们所想的一样
She swallows the grass, just as you'd expect,
但看看接下来会发生什么
but watch what happens next.
她反刍出一个半消化的草球 再重新消化一遍
She regurgitates a ball of partly digested grass and processes it all over again.
这叫做咀嚼反刍食物
It's called chewing the cud.
经由不仅一次而是两次地消化草 它们能提取出全部仅有的氮
By digesting grass not once but twice they can extract every last drop of nitrogen.
牛羚也反刍
Wildebeest chew the cud too,
但它有另一种寻找氮的方式
but have another strategy to find nitrogen
这招引发了地球上最大 规模的野生动物奇观之一
that gives rise to one of the greatest wildlife spectacles on earth.
每年有150万头牛羚 迁徙1500公里穿越东非
Every year, one and a half million wildebeest migrate 1500 kilometres across east Africa,
寻找最好的草
in search of the best grass.
因为有些草氮含量更多
Because some grass is richer in nitrogen.
随着草越来越长 里面的氮含量也随之稀释
As grass gets longer, the nitrogen it holds becomes diluted.
最终 草的每克氮含量如此稀少 对牛羚来说已经没有价值了
Eventually the grass holds so little nitrogen per gram it becomes useless to the wildebeest.
一直保持移♥动♥的策略 意味着牛羚可以找到最好的草
The strategy of staying constantly on the move means the wildebeest find the very best grass.
费尽周折 从整个草原上获取了氮
Having done the hard work, obtaining nitrogen from across the grassland,
每头牛羚都形成了 一块浓缩的蛋白质
each wildebeest forms one concentrated package of protein.
现在掠食动物可以占便宜了
And now the predators can take advantage.
猎豹等着牛羚 在自己冲出去之前奔跑
The cheetah waits for the wildebeest to start to run before she charges
因为猎物移♥动♥时的冲力 让它们更容易被撞翻
because the momentum of moving prey makes them easier to knock over.
母亲不得不为幼崽捕食 直到它们至少1岁为止
The mother will have to hunt for her cubs until they're at least a year old.
即便如此也只有5％幼猎豹能免于 饿死或被吃掉的命运 而活到成年
Even so, only 5 percent of cheetah cubs avoid starvation and predation to make it to adulthood.
争夺宝贵的蛋白质之战十分激烈 所以它们必须快速进食
Competition for precious protein is fierce, so they must eat fast,
赶在秃鸶成群结队来吃死尸 并撵走它们前
before the vultures arrive in enough numbers to bully them off the kill.
4只猎豹能在仅仅15分钟内 吞食掉一头这么大的猎物
4 cheetahs can devour a prey animal of this size in just 15 minutes.
但猎豹的力气不足以 藏起或者守住它们的猎物
But cheetahs aren't strong enough to hide or guard their catch,
因此 秃鸶最终抢到了食物
so eventually the vultures get their turn.
牛羚以及大多数猎豹的狩猎对象 都在氮含量相对高些的草地上觅食
The wildebeest and most of the cheetahs other prey feed in comparatively high nitrogen grass areas.
猎豹是跟着猎物移♥动♥的
And the cheetah follow their prey.
然而 不仅是最好的草 为非洲出名的野生动物提供养分
But it's not just the best grass that supports Africa's famous wildlife.
甚至在氮含量最低的区域 像这犀牛般大的动物还是能存活
Even in the lowest nitrogen areas, big animals like this white rhino still manage to thrive.
她采用了不同的策略 其实要归功于她的体型
She achieves this with a different strategy that actually relies on her size.
从头到尾她身长3米 和卡车一般重
From head to rump she measures about 3 metres and weighs the same as a truck.
这让她成为了 世界上最大型的动物之一
This makes her one of the world's biggest animals.
她硕大的身体内 长有一个巨型的发酵室
Her huge body houses an enormous fermentation chamber.
这让她能够经由吃下大量的草 来弥补草的低品质
This allows her to compensate for the low quality of the grass by eating a lot of it
并让它们慢慢地发酵
and allowing it to ferment slowly.
实际上她一天12小时都在吃
In fact she spends 12 hours a day, solidly eating.
但这行动迟缓的庞然大物 也为其他动物提供了食物
But this gentle giant also provides a food supply for other animals.
红嘴牛惊鸟在吃扁虱时 搭了个便车
Red-billed oxpeckers hitch a ride, while feeding on her ticks.
而牛背鹭则跟随犀牛 穿越了草原
And cattle egrets follow the rhino across the grassland,
补食它巨大的蹄子上 蜂拥而出的昆虫
feasting on the insects flushed out by its huge feet.
值得注意的是犀牛还经由制♥造♥ 养分热点区域帮助其他食草动物
Remarkably, rhinos also help other grazers by creating nutrient hotspots.
犀牛排便排尿时 它们会在排泄场所排出大量的氮
When rhinos defecate and urinate, they concentrate a lot of nitrogen in one spot.
在这里 就会新生出富含氮成分的草
Here new nitrogen-rich grass can sprout.
割掉长长的草 有助于矮草的生长
And cropping the long grass down encourages the growth of shorter grass species.
现在草更有营养了 挑食的黑斑羚可以来此觅食了
Now that it's more nutritious, the fussy impala can come here to feed.
犀牛将草质低劣的地域 变成了富含氮成分的草地
The rhinos have changed areas of poor quality grass into nitrogen-rich meadows,
这使它们成为了 重要的生态系统工程师
which makes them important ecosystem engineers.
但在某些区域 并没有这样的草原
But in some areas, no such meadows can be found.
巴西
Brazil.
艾玛斯国家公园的草原 氮含量十分低
The grasslands here in Emas National Park are very low in nitrogen.
这里没有像野牛或牛羚这样的 大型食草动物群
And no large grazing herds like bison or wildebeest exist.
所以这里最高级的掠食动物
So the top predator in these grasslands
进化出了与猎豹和狮子 不同的生存策略
has developed different survival tactics to those of lions or cheetahs.
鬃狼
The maned wolf.
长长的腿 有助于它在高草上扫视
Its long legs help it see over tall grass,
它大大的耳朵帮助它找到猎物
and its large ears help it find its prey.
其他狼成群狩猎
Other wolves hunt in packs.
但在这里 食物如此稀少 两匹狼只有在交♥配♥时才聚在一起
But here, the pickings are so poor that two wolves only come together briefly to breed.
否则其中一只就必须离开
Otherwise one of them has to go.
狼费了九牛二虎之力 才能获得很小份量的晚餐
This wolf spends a lot of energy catching his dinner for a small reward.
它试图透过跳动、跺脚 赶老鼠出来
He tries to provoke a mouse into running by jumping up and thumping his feet on the ground.
狼仔细听着 静候最微弱的动静 直到老鼠移♥动♥后抓住它
The wolf listens and waits for the tiniest sound until the mouse moves and blows its cover.
它每天能走30公里 寻找足够的口粮
He can walk thirty kilometres a day to find enough morsels of food.
这种生活方式为鬃狼的成长和 身体组织的维护提供了足够的氮
This lifestyle provides just enough nitrogen for the maned wolf to grow and maintain its tissues.
但为了获得足够的能量 狼必须采用一种特殊的进食方式
But to get enough energy, the wolf has put itself on an extraordinary dietary supplement.
鬃狼大多数在晚上狩猎
Maned wolves do most of their hunting at night.
惊人的是 这些狼果 才是它要找的东西
Surprisingly, these lobeira fruit are exactly what he's looking for.
这种水果含有蛋白质和碳水化合物
This fruit contains protein and carbohydrates
给狼提供了额外的氮 和所需的能量
giving the wolf the extra nitrogen and energy he needs.
狼果是如此重要 它占狼饮食结构的一半
Lobeira fruit is so important, it forms up to half the wolf's diet.
更让人惊讶的是 狼还会自己培育水果
And more surprising still, the wolves effectively farm their own fruit.
鬃狼需要标记自己的地盘
Maned wolves need to mark their territory.
它们在高处占地槃 这样其他狼 就能从远处看到、闻到它的领地
They do it on high spots where other wolves will be able to see, and smell it, from much further away.
在塞拉多平原 切叶蚁巢 构成了少有的高地之一
On the flat Cerrado, leaf-cutter ant nests form one of the few raised areas.
不久后 生活在下面巢穴的切叶蚁 发现了狼的粪便
Before long, the leaf cutter ants that live in the nest below find the wolf's faeces.
而这些半消化的 水果残骸令它们难以拒绝
And those partly digested remains of fruit are irresistible.
它们甚至还吃了一点老鼠肉
They even try bits of the mouse.
但蚂蚁在找的是其他东西 而且有只蚂蚁已经找到了
But the ants are searching for something else and one of them has just found it.
一颗圆圆的狼果种子
The round seed of a lobeira fruit.
这些种子占狼粪的一多半
Over half the faeces are made up of these seeds.
蚂蚁小心翼翼地 将每颗种子搬运回巢穴
And the ants carefully carry each seed into the nest.
之后 出于某个未知的原因
Later, for some unknown reason,
许多种子会被从巢里扔出来
many of the seeds will then be ejected from the nest.
这些是被扔掉的 一起扔掉的 还有蚂蚁排泄物和挖掘的废弃物
These are dumped, along with the ant's faeces and their digging refuse,
这些一起成为了混合肥料
together it all acts as compost.