外星世界（2020）

will come up to one another,
然后表演某种战舞
and they will, kind of, xa0 have a little dance.
他们试图判断
And they will try and judge
哪一个的长杆更长一些
which of the two of themxa0 has the bigger stalks.
好了 对峙开始了
There they are. That's the standoff!
胜者会留下来 输的那个会走开
The winner of that will remain where they are and the loser will then toddle off.
胜者有权去接触雌性 和她进行繁殖
That winner then will gain access to the female, and be able to reproduce with her,
通过这种方式 雄性突眼蜂 可以把他的遗传特性传下去
and that way can pass onxa0 the genetics that he has,
这些遗传特性也包括更长的眼睛长杆
which will includexa0 that of a longer eye stalk.
-好 拍到了 -你拍到了吗？
Yes! Got it. Are are you on it?
太棒了
Oh, It's fantastic.
通常时间很短 它们就会飞走xa0太棒了
Normally, it's a second and they're gone. This is fantastic.
雄性突眼蜂何必花大力气
Why would the male stalk-eyed flyxa0 go to the effort
拥有这样巨大的眼睛长杆？
of having these enormous eye stalks?
其中的道理是 你给雌性一个明显的信♥号♥♥
Well, the idea is that you arexa0 conspicuously signaling to the female
你有能力把这样巨大的资源
that you can have this incrediblexa0 investment of energy into this resource
使用在一个完全无用的东西上
that is completely needless.
你能幸存下来
And if you can still survive,
你能继续飞行 生活 不被捕食
if you can carry on flying and livingxa0 and not getting predated upon,
尽管头上戴着这对浪费能量的奢侈品
and still have this. . . wasteful extravagance coming out of your head,
那就说明 和你一起繁衍后代是个不错的选择
then you're gonna be a pretty good bet to reproduce with.
在亚特剌斯
On Atlas,
雄性空中食草兽的长尾 显示他是一个理想的选择
the long tailxa0of the malexa0sky grazer shows he's an ideal choice. . .
做下一代的父亲
to father the next generation.
但母亲不能在空中产卵
But the mother can't lay her eggsxa0 in the sky.
于是她降落到地面
So she's come down to land.
由于重力的原因 她太重了 无法让自己回到天空
Because of the gravity, she's too heavyxa0 to launch herself back into the sky.
为了创造新的生命 她必须献出自己的生命
To create new life, she must surrender her own.
孩子们在离母亲去世不远的地方成长
The babies grow up closexa0 to where their mothers die.
现在它们需要离开地面 进入空中
Now they need to get off the groundxa0 and into the air.
但食腐动物在等待
But scavengers lie in wait.
没有骨头的生命
Boneless creatures
没有骨架让它们成型
with no skeleton to give them form.
它们通过包裹和溶解猎物进行猎杀
They kill by enveloping and dissolving their prey.
空中食草兽才刚刚孵化 但它们已经处在巨大的危险中
The sky grazers have only just hatched, xa0 but already they're in grave danger.
现在没有了回头路
And now, there's no going back.
（南非 卡拉哈里沙漠）
每一天在地球上
Every day on Earth,
幼小的动物为了生存
young animals have to overcomexa0 terrible odds,
必须战胜渺茫的生存机会
if they're to survive.
60%的猫鼬无法存活一年
Sixty percent of meerkats don't make itxa0 to their first birthday.
在幼年猫鼬的早期
For a young meerkat, in their early life,
这里有许多危险
there's a lot of danger here.
出生后的好几个月 它们都非常脆弱
They're vulnerable for many monthsxa0 after they're born. . .
特别是它们从地洞里出来的 头一、两个月
but particularly in the first month or two after they emerge from the burrow.
捕猎者无处不在 这是一个一直存在的危险
Predators are everywhere, and a constant danger.
这个区域有蛇…
There are snakes in this area
它们会吃年幼的猫鼬
that will eat a young meerkat.
年幼的猫鼬在群体里是安全的
A young meerkat is safe within a group,
但如果落在了后面 就很容易受到伤害
but if it lags behind, it's vulnerable.
蝎子一直是个威胁
Scorpions are a constant threat.
幼崽完全没有能力
The young are really completely incompetent,
开始的时候 完全不知道如何对付蝎子
and totally ignorant when it comesxa0 to dealing with scorpions, initially.
但它们无法永远逃避这种危险
But they can't avoidxa0 this danger forever.
最终它们得学会如何化解威胁
They're going to eventually have to learn how to neutralize the threat.
年幼的猫鼬第一次面对蝎子
The first time that a young meerkat faces a scorpion
并且得自己搞定的时候
and it has to deal with it itself
这也许是一个可怕的遭遇
is probably a terrifying encounter.
现在是见分晓的时候
This is a real moment of truth.
这是一个真正的通过仪礼 因为一旦它们能够自己解决
It's a real rite of passage, because once they've managed to do that themselves,
它们就能真正进入自己捕食的阶段
then they really are at a stage where they can start to forage by themselves
变得独♥立♥ 变成群体中有用的一员
and become independentxa0 and be a useful group member.
它们成功摆脱了作为幼兽的脆弱性
So, they've really managed to escape the vulnerability of being a pup
完成了向成年的转变
and made that transitionxa0 into being an adult.
这是走向成年道路迈出的一步
It's one step on the road to adulthood,
但之后的道路也绝不是一帆风顺的
but it's by no means plain sailingxa0 after that.
前面还有很多威胁
There are a lot of threats out there,
它们必须继续学习 才能到达成年状态
and it will have to continue to learnxa0 in order to reach adulthood.
如果空中食草兽想要长大
If the young sky grazers are to grow up,
它们没有选择
they have no choice.
现在是起飞的时候
It's time to fly.
即使在空中 它们也不是安全的
Even in the air, they're still not safe.
在亚特剌斯
On Atlas,
能否生存完全看概率
survival is a game of chance.
一代一代 生命延续下去
Life goes on from one generation to the next.
至少暂时是这样
At least for now.
亚特剌斯的巨大重力 把小行星带入坠毁轨道
The strong gravity of Atlasxa0 pulls asteroids onto a collision course.
它们绝大部分在大气层中燃烧掉
Most burn up in the atmosphere.
但有个威胁一直存在 体积较大的小行星会穿越大气层
But there's a constant threatxa0 something big will get through. . .
重设这个星球上生命的轨迹
and reset the course of lifexa0 on the planet.
由于地球上的重力 弱于在亚特剌斯上的
Because gravity is weakerxa0 on Earth than Atlas,
小行星撞击没那么频繁
asteroid strikes are less frequent.
但撞击一旦发生 那将会是灾难性的
But when they do occur, they can be catastrophic.
这里是尤卡坦半岛
This is the Yucatán Peninsula.
七万平方公里的热带雨林
27, 000 square miles of tropical jungle.
但雨林里隐藏着无数地陷 它们被称为天坑
But hidden within the junglexa0 are numerous sinkholes called cenotes.
（墨西哥 尤卡坦半岛）
这些是进入巨大地下洞穴系统的入口
These are entrances to vast underground cave systems.
半岛上没有露于表面的河流和溪流
There's no surface rivers or streams in the peninsula,
因此唯一的水源在地下的洞穴中
so the only source of water is underground in caves.
但真正有意思的事情 在于这些天坑的位置
But the really interesting thingxa0 is the location of these cenotes.
尽管半岛上有大约一万个 甚至更多的天坑
Although there's probably 10, 000xa0 or more cenotes across the peninsula,
在西北角
in the northwest corner. . .
它们相当精确地分布在一个半圆形上
they occur in a very well-definedxa0 semicircle.
如果我们把这个半圆形延长至 墨西哥湾
If we follow that semicirclexa0 out into the Gulf of Mexico. . .
我们得到一个完整的圆形
we now have a complete circlexa0 that marks what one would expect
刚好符合 小行星撞击形成的陨石坑边缘
from the edgexa0 of an asteroid impact crater.
650万年前
65 million years ago,
重力将一颗小行星 吸引进我们的太阳系
gravity pulled an asteroidxa0 into our solar system.
它撞击在我们的星球上
It smashed into our planet,
造成地球上75%物种的灭绝
causing the extinctionxa0 of 75 percent of life on Earth.
小行星撞击制♥造♥了足够多的碎屑
The asteroid strikexa0generatedxa0 enough debris
在两年时间里挡住了阳光
to block out sunlight for two years.
世界陷入黑暗
A world plunged into darkness.
万物无法生长
Nothing could grow.
如果受到足够大的小行星撞击 亚特剌斯也会发生这种情况
This would happen on Atlas if a big enough asteroid hit the planet.
在天坑里生存很难
Cenotes are difficult places to survive. . .
正如650万年前的地球
just like the Earth was 65 million years ago.
一个物种需要具有什么样的特性 才能免于灭绝？
What are the characteristics thatxa0 a species needs to survive an extinction?
这里有个家伙
Somebody's in here.
鳄鱼是一种适应性很强的动物
So, crocodiles are very resilient animals.
它们可以在水中和陆地上生存
They live both in the water and on land.
它们是通才 无需特别的食谱
They're generalists. They don't require a specific diet.
它们几乎什么都吃
They'll eat almost anything.
它们有什么吃什么
Whatever is available is good enough,
只要有就好
they'll take it.
在这个天坑里
Here in this cenote,
一个家伙掉了进来 被困住了 无法出去
one's fallen in, gotten trapped, no way out. . .
不知怎的 通过某种方式…
Somehow, some way. . .
它成功了
he's succeeded.
它们是幸存者
They're survivors.
在一个变幻的世界 最好做个通才
In a changing world, it pays to be a generalist,
不要做专家
not a specialist.
如果有一个足够大的小行星撞击了 亚特剌斯
If a big enough asteroid hits Atlas,
空中食草兽和捕猎者的末日就来了
the sky grazers and predatorsxa0 would be doomed.
它们过于专于一技 无法应对变化
They're too specializedxa0 to cope with change.
没有骨头的食腐者是通才
The generalistsxa0 are the boneless scavengers.
就像鳄鱼一样 它们什么都吃
Like crocodiles, they eat anything. . .
可以在任何环境生存
and live anywhere.
在这个想象中的高重力世界
On this imagined high-gravity world,
它们可能成为伟大的幸存者
they could be the great survivors.
如果换个世界