侏羅紀搏擊俱樂部 第103期:侏羅紀時期氧氣水平多高

Allosaurus was really the first of the truly big meat-eating dinosaurs that was found and was the one from fairly complete remains.

異特龍真的是被發(fā)現(xiàn)的第一種大型肉食恐龍而且其骨骼保存相當完整。

It was the Tyrannosaurus-Rex before there was a Tyrannosaurus-Rex, both in terms of geological time and its discovery.

它是霸王龍之前的霸王龍，從地質(zhì)時間和被發(fā)現(xiàn)的時間上都是如此。

Powerfully muscled, Allosaurus was able to hunt huge herbivores, like the two-ton stegosaurus.

異特龍肌肉發(fā)達，能夠捕獵大型植食動物，比如重達兩噸的劍龍。

Allosaurus in its time was the top predator.It was a combination of a lot of really useful traits for a predator.

異特龍是那一時期的頂級掠食者。它身上集合了很多掠食者非常有用的特征。

It had powerful jaws with pretty sharp teeth.

它的雙頜有力還有很鋒利的牙齒。

It had large claws on its hand which are very useful for gripping and tearing.

它的前肢上有巨大的爪子，在握緊和撕扯時很有用。

So it combined a lot of useful traits as a hunter.

所以作為一個獵手它結合了很多有用的特征。

Allosaurus has got relative long arms for a big predatory dinosaur.

異特龍在大型掠食恐龍里前肢是比較長的。

Most predators have these little arms and they are not very effective weapons.

多數(shù)掠食者前肢短小而且它們不是非常有效的武器。

But Allosaurus is different. He's got three enormous claws on each hand.

不過異特龍并不一樣。它的每個前肢上有三個巨大的爪。

And listen, you don't have the big claws to play the piano.

注意，長出大爪子可不是要彈鋼琴。

You have big claws to rip somebody's head off.

有大爪子是要把別人的腦袋扯下來。

I think another way to look at Allosaurus is if you were to take a wolf and make it into a two-ton animal, put on two legs, put Edward-Scissorhands-like arms on it with giant claws, and then maybe put a skull of an alligator on top of that carnivorous animal.

我覺另一種看特異龍的方法，就是把一頭狼放大變成兩噸重，讓它兩足行走，換上剪刀手愛德華那樣的帶長爪的前肢之后，再把短吻鱷的腦袋給這個肉食猛獸安上。

Allosaurus was a fast, strong, ferocious beast.

異特龍是一個迅速、強壯、兇猛的野獸。

It stood about 3 meters tall, measured nearly 12 meters in length, and weighed up to 4 tons, making Allosaurus one of the biggest meat eaters of its time.

它站起來有三米高，長度接近十二米，重可達四噸，這使得異特龍成為那一時期最大的肉食者之一。

The reason why Allosaurus and other dinosaurs were able to grow so big is because the oxygen levels were much higher back then than they are today.

異特龍和其它恐龍能長到如此巨大，是因為那時的氧氣水平比現(xiàn)在高得多。

And so dinosaurs were able to extract oxygen without much effort, and therefore they could carry a heavier load and live more active lives even though they were huge.

所以恐龍不用費力就能獲得氧氣，因此它們能挑更重的擔也能活得更活躍，即使它們是巨大的。

During the late Jurassic period, oxygen levels have been estimated to be as high as 35 percent, higher than our current 21 percent oxygen level, making life much easier for the large dinosaurs.

在侏羅紀時晚期，氧氣水平據(jù)估計高達35%，比我們現(xiàn)在的21%高，這使得大型恐龍的生活容易得多。

So how on earth could anyone know what the oxygen level was a million years ago?

那么我們到底是怎么知道一百萬年以前氧氣水平有多高呢?