探秘野性赤道（2020）

太平洋上遍布着奇特的火山岛屿
Across the Pacific lie extraordinary volcanic islands.
从著名的加拉帕戈斯群岛 到微不足道的珊瑚岛
From the famous Galapagos archipelago to obscure tiny atolls.
这些赤道热门地区的海滨动物们 独特又奇异
These equatorial hotspots harbor animals that are truly unique and bizarre.
有会游泳的爬行动物,不会飞翔的鸟类
Reptiles that swim. Birds that can't fly.
移居而来的企鹅
Displaced penguins.
翩翩起舞的海鸟
Dancing sea birds.
和世上最大的陆地甲壳动物
And the world's largest land crustacean.
赤道的秘密
加拉帕戈斯
赤道，一条横跨了
The equator...the line of latitude
十一个国家和四大洋的纬线
that crosses eleven countries and four oceans.
这里常年靠近太阳
Here the Earth remains close to the Sun all year round,
将昼夜划分成两等份
dividing night and day into equal halves.
坐落在赤道上的十二座火山岛
Sitting on the equator is a group of 20 volcanic islands.
一起组成了著名的加拉帕戈斯群岛
These make up the famous Galapagos archipelago.
在南美大♥陆♥以西1000公里处
Six-hundred miles west of continental South America...
这些丰富的自然大熔炉
these rich evolutionary melting pots are strongly influenced
受三股洋流所影响
by three major ocean currents.
加拉帕戈斯
虽然南美洲的洋流给这些岛屿
Although the islands are dominated by cold water
带来了大量的寒冷海水
due to the Humboldt Ocean current from South America...
但这里的温度却由 北下的季节性暖流所决定
it's tempered by a seasonal warmer current from the north.
因此太平洋温暖海域常见的动物
As a result, species often found in warm seas of the Pacific
和寒冷海域的动物一起生活
mix with cold water animals
而寒冷海域的动物一般是在 更南或更北的地方繁衍生息
that traditionally thrive further north or south.
企鹅 海狮和信天翁
Penguins, sea lions, and albatrosses
在海洋寒流里茁壮成长
thrive in these cold water currents.
乌龟 锤头鲨和热带鱼类
Turtles, hammerheads, and exotic fish
在西边悠闲自得
are found on the western side.
陆地上生活着陆龟 爬行动物
On land, there are tortoises, reptiles,
以及各种海鸟
and sea birds of all types...
它们在这片乐土上 找寻着各自的进化方向
finding their own evolutionary niche in this equatorial paradise.
加拉帕戈斯的动物们独具一格
Galapagos animals are often not what they seem.
鸬鹚在世界很多地方
Cormorants are highly adaptable hunters
都是适应能力超强的猎手
seen in many parts of the world.
但在这里 它们只栖息在 靠近西部山脊的两座岛屿上
But here they are found on just two islands
in the western reaches.
而且这里的鸬鹚种类独一无二
And the Galapagos species is uniquely different.
它们不会飞
It can't fly.
这里没有它们的天敌
The lack of predators on these volcanic islands
导致它们丧失了飞行的能力
meant that the cormorants gave away the power of flight.
相比于其他会飞的近亲 它们的翅膀短小又脏乱
Their wings are tiny and scruffy compared to their flying cousins.
胸骨也不再隆起
The breastbone has also lost its pronounced ridge,
那本应该连接着丰满的羽翼
where well-developed wings normally attach.
飞行往往对于鸟类入水捕鱼非常必要
Flight seems essential for most birds when hunting their aquatic prey.
但在费尔南迪纳岛上
But here on Fernandina Island,
它们早就适应了 在浅海区寻找所需的一切
they've adapted to find everything they need in the shallow seas...
食物 甚至是筑巢材料，即便在这样没有树的岛上
food and on an almost treeless island,nesting materials.
它们也能用新鲜海草代替树枝和叶子
Fresh seaweed takes the place of twigs and leaves.
雌性鸬鹚将海草放入还没建好的巢里
The female adds the seaweed to the nest she's building.
这样建好的巢能保护鸬鹚蛋 免受坚硬的锯齿状火山石的影响
When complete, it'll cushion the eggs from the jagged,hard, volcanic rocks.
这个在岛屿最北边的岩石湾
This rocky cove in the island's northeast
居住着约十万只鬣蜥
is home to around 100,000 marine iguanas.
它们是冷血动物 所以每天早上它们在岩石上一一散开
They're cold-blooded, so in the morning
they spread far and wide over the rocks
享受完赤道烈日的阳光再去觅食
to soak up the hot equatorial sun before foraging.
在繁殖季节
In the breeding season,
雄性鬣蜥会为了争夺领地而打斗
the males will also engage in territorial fights,
而让雌性鬣蜥安心享受日光浴
while letting the females sunbathe unmolested.
它们头顶着头 互相叫嚣着
The street-fight consists of head-butting and posturing,
还会拱起背嵴
and raising their dorsal crest.
它们不会真的撕咬彼此
They'll never actually bite each other.
失败者会小心翼翼地退出争夺
The loser carefully backs away,
让出岩石上的领地
conceding space on the rock.
终于 鬣蜥的体温升高
Eventually, the iguana's core temperature
足以支撑它们潜入海水
will be high enough for a dip in the ocean.
冷血的它们需要赤道的阳光来获取温度
Being cold-blooded means that heat needs to come from the equatorial sun.
带头的雄性大鬣蜥 小心翼翼来到海边
The first big males cautiously make their way down to the water's edge.
那里有小片植被
There's little vegetation.
凭借超凡的适应能力 它们啃食海床为生
So through an extraordinary adaptation,
they graze off the seabed instead.
而在几十米开外的海底 有大♥片♥的藻类
Just a few hundred feet offshore,
there's an underwater algae meadow.
然而只有最大的雄性鬣蜥
Only the biggest males, due to their larger size,
才能够凭借体格潜到那里
can dive down here.
它们也是唯一会潜水的鬣蜥
They are also the only iguana species that does dive.
陆地上的温度一般在20到25度
On land, the temperature varies between 69 to 84 Fahrenheit.
但是海水温度只有15度左右
But the ocean water is only 60 degrees,
足以冻死一只冷血爬行动物
low enough to kill a cold-blooded reptile.
但是雄性鬣蜥自有妙招
But the male has a couple of coping strategies.
它把血液集中在主要器官 以保持他们正常运行
It draws in its blood to the core organs keeping them functioning.
同时大幅降低心跳速率
It also drastically lowers its heart rate.
以此来应对
This way, they can survive the 20-degree plunge
将近10度的体温变化
in their body temperature.
不过他们最多只能在水下待两个小时
But two hours in the cold water is their limit.
清晨慢慢过去 另一只大鬣蜥也跳入水中
As the morning wears on,
another big iguana takes the plunge.
它凭借长长的爪子 在强劲的水流中自如游动
He braces himself against the strong current with his long claws.
它必须用力抓紧
He'll have to hang on tight.
以免被海水冲得太远
He can't afford to be washed out too far...
它必须赶在体温降低之前
because it's a race against time to eat
抓紧时间觅食
before his body temperature gets too low.
它们天性贪吃
They are voracious.
好在这些藻类 在几天内就能再次生长出来
Luckily, the algae replenishes quickly, in just a few days.
鬣蜥需要浮出水面换气
The iguanas surface often to breathe.
30分钟已经是它们的极限了
Around 30 minutes is their observed limit.
它们似乎很清楚 什么时候该回到安全地带
They seem to know when it's time to return to the safety of the shore.
但是长时间潜水后
But after a long dive,
雄性鬣蜥由于体温过低
the big males are sometimes barely able to swim
有时会没法游泳
because of their low body temperature.
如果被冲进大海 那就必死无疑了
If they're swept out to sea,they'll face certain death.
它们必须得赶快游回温暖的海岸
They must fight their way back to the warmer shores.
它成功了
The male makes it back.
如果只有大型的雄性鬣蜥能潜海觅食
But if these large males are the only ones who can feed underwater,
那雌性或小型的雄性鬣蜥 又是如何觅食的呢?
how do the females and smaller males eat?
加拉帕戈斯岛的大型海洋鬣蜥
The large marine iguanas of the Galapagos
能够从水下丰富的藻类中获取食物
get their sustenance from the extensive underwater algae meadows.
但小型的鬣蜥是如何生存的呢?
But how do smaller iguanas survive?
它们靠的是耐心
Patience is key.
它们等待潮水退去 海藻床露出水面
They wait for the tide to be low enough to expose the same algae beds.
但它们也要在潮水回来前与时间赛跑
But they too have a race against time before the turning tide.
费尔南迪纳的北边是道格拉斯角
In the north of Fernandina is Cape Douglas.
这里的另一种冷血爬行动物 适应了更冷的海水
Here another cold-blooded reptile has adapted to the colder waters.
加拉帕戈斯绿龟
The Galapagos green turtle.
因为没有鬣蜥那般长长的爪子
It lacks the iguana's large claws,
它们不得不在海里边游动边啃食藻类
so has to swim against the tide to graze on the algae.
它们是唯一在 加拉帕戈斯海滩上筑巢的物种
They're the only species to nest on the Galapagos beaches.
但它们却不是这里唯一的外来物种
But the turtles are not the only unexpected immigrants here.
在圣克鲁斯岛中部 由于海水与淡水的混合
On the central island of Santa Cruz,
sea water mixes with fresh water
海岸附近形成了咸环礁湖
to produce briny lagoons near the coast.
这里的鸟类几乎都忙忙碌碌
Here, unlikely birds can be found wading...
火烈鸟
flamingos.
这些惹眼的动物觅食时把头朝下
These striking waders feed with their heads upside down.
它们的喙生来就可以过滤掉 食物里的泥沙
Their beaks are designed to separate mud and silt
from the food they consume.
它们大多捕食的是小型甲壳动物
They eat mostly small crustaceans,
因为小型甲壳动物富含胡萝卜素
which contain a carotene pigment
可以让它们的羽毛呈现粉红色
which cause their feathers to turn many hues of pink.
在这里定居的火烈鸟约有350只
Around 350 live here permanently,
其他的火烈鸟来自加勒比群岛
immigrants from the Caribbean islands
一个距加拉帕戈斯 东北部约1700公里的岛屿
1,100 miles northeast of the Galapagos.
它们很可能随信风而来
It's possible these birds arrived on the trade winds
这种情况只会在热带发生
that only occur in the tropics.
加拉帕戈斯群岛地理位置非常独特
The Galapagos are positioned in a very unique location