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The equator. It runs across the scorched plains of east Africa.
赤道。它橫跨東非洲的焦土平原。
This is as far from the Poles as you can get.
它是離兩極最遠的地方。
But ice and snow are here too up in the mountains.
但這里也有冰和雪，就在山上。
Every continent on earth has such high snowfields.
地球上每塊大陸都有這種海拔高的雪原。
And each has its own community of animals that have adapted in their own way to the crushing conditions that come with the cold.
每個雪原也都有其獨特的動物群，用自己的方式適應伴隨寒冷而來的嚴酷條件。
Dawn in east Africa, on the high slopes of mount Kenya... 4,000 metres up.
東非的黎明，在肯尼亞山的高坡上，四千米之上。
The temperature is just beginning to creep above freezing.
溫度才剛升至冰點以上。
It's hardly the place where you would expect to find a cold-blooded reptile.
你通常不會期待在這種地方看到冷血爬行動物類。
But there is one that lives up here, the high-casqued chameleon.
但就有一種住在上面這邊，頭盔變色龍。
This female has survived the night's freezing temperatures
這只雌性從夜晚的結冰溫度中撐了過來，
by allowing both her metabolism and her heart rate to drop significantly.
借由大幅降低自己的新陳代謝率和心率。
Now, in the morning, she needs to eat.
現在到了早上，它需要進食。
But it's so cold, she can't move her legs.
但太冷了，它移動不了它的腿。
Her spring-loaded tongue, however, still works.
但是它像裝有彈簧一樣的舌頭還能用。
As the sun rises higher in the sky, frozen land begins to thaw.
隨著太陽在空中越升越高，凍結的土地開始解凍。
And the giant lobelias spread their leaves to soak up the sunshine.
巨山梗菜已經打開，它們的枝葉來吸收陽光。
With her body temperature still only five degrees celsius, the chameleon becomes more mobile, and climbs up to bask in the sun.
雖然體溫還只有攝氏五度，變色龍變得更有活動力，往上爬來曬太陽。
Her skin darkens... enabling her to absorb the sun's heat more quickly.
它的皮膚顏色變深，讓它能更快吸收太陽的熱度。
She is pregnant, and soon her temperature reaches 20 degrees celsius, which gives her the energy she needs to give birth.
它懷孕了，體溫很快就會達到二十攝氏度，能給它生產所需的能量。
Most chameleon species lay eggs, but here it's too cold for an egg to develop in the open.
大多的變色龍物種都生蛋，但這里太冷，蛋無法在外發育。
So she produces live young. It takes just an hour for her to give birth to six baby chameleons.
所以它用胎生的方式生產。生六只變色龍寶寶，只花了它一小時。
One of the advantages of life on the frozen peaks is that there are fewer predators here, and less competition for food.
生活在冰凍的山頂上，其中一項好處就是這邊沒什么掠食者，覓食時也比較少競爭對手。
But there's a reason why comparatively few reptiles live in the high mountains.
但相較之下，很少爬行動物類住在高山上是有理由的。
As the sun sets, the temperature falls to below zero in a matter of minutes.
日落之后，溫度會在幾分鐘內降到零度以下。
The babies must act fast.
寶寶們必須動作快。
To escape the nightly freeze, they need the cover of thick vegetation.
為了避免在夜晚被凍結，它們需要厚植被的覆蓋。
A young chameleon caught out in the cold, will quickly lose its ability to move, and may well die.
一只年輕的變色龍如果暴露在寒冷之中，會很快失去行動能力，然后很可能會死亡。
Most, however, react instinctively and find shelter as quickly as they can.
但它們大多數都會本能地盡快找掩蔽。
