Meet the world's first dinosaur.

來看看世界上第一隻恐龍。

No, down here.

不對，在下面。

Eoraptor would have only come up to about your knees.

始盜龍的身高只到你的膝蓋。

In fact, most early Triassic dinosaurs were on the shrimpy side, including predators like the fierce, mule-sized Coelophysis.

事實上，大多數早三疊世的恐龍都處於瀕臨滅絕，包括肉食動物，比如兇猛的騾子，體型大小的腔骨龍。

But after volcanic eruptions took out their competitors and ushered in the Jurassic period, everything changed.

但火山爆發後，殺光了他們的競爭對手，並迎來了侏羅紀時期，一切都改變了。

New species exploded onto the scene like the plate-covered Scelidosaurus.

新物種的數量激增，就像被板塊覆蓋的腿龍。

And bigger herbivores meant bigger meat eaters too.

更大的草食動物，也代表有更大的肉食動物。

Predators, like the Dilophosaurus got to be six meters long.

肉食動物，比如六公尺長的雙脊龍。

But they were no match for the real giants of the era, Prosauropods.

但牠們都不是這個時期真正的巨人，原蜥腳類。

Now, these leaf eaters weren't much bigger than a giraffe.

這些吃樹葉的恐龍並沒有比長頸鹿大。

On the inside, they looked like a bird.

他們的體內看起來像一隻鳥。

And it's this anatomy that enabled Prosauropods to evolve into the largest dinosaurs of all time.

正是這種解剖學使原蜥腳類進化成歷史上最大的恐龍 。

So let's take a closer look.

讓我們來仔細看看。

Specialized lungs and air sacs allowed them to take in more oxygen and also made their skeletons lighter, hollowing out bone into a sturdy, honeycomb structure.

專門的肺和氣囊可以吸收更多的氧氣，也使牠們的骨骼更輕，中空的骨骼變成堅固的蜂巢狀結構。

Millions of years of evolution later, you can see the difference.

數百萬年的進化之後你可以看出差異 。

Ornithischian dinosaurs like Triceratops and Stegosaurs lack these air sacs and as a result, most of them weren't very big.

三角龍和劍龍屬於鳥臀目恐龍，缺少這些氣囊，因此牠們大多數的體型並不大。

While Triceratops and Stegosaurus grew up to eight meters long, bird-like theropods like Tyrannosaurus grew twice as large.

當三角龍和劍龍長到八公尺長時，像暴龍這樣的獸腳亞目類恐龍長了兩倍大。

But it was the sauropods like Brontosaurus, Diplodocus and Brachiosaurus who reached enormous proportions.

但蜥腳下目類的恐龍，比如雷龍梁龍和腕龍達到了巨大的比例。

Like the theropods, these titans used air sacs to breathe and had light, hollow bones.

像獸腳亞目類恐龍一樣，這些巨人使用氣囊來呼吸，而且有很輕的中空骨骼。

But they had another reason for outgrowing everyone else at the time: survival.

但他們還有另一個原因比其他恐龍長得更大：倖存。

Their size was a great defense against predators and the largest of the bunch stood over 26 meters long, weighed 55 tons or more,

牠們的體型是抵禦肉食動物的有力武器，最大的一群超過 26 公尺長，重達 55 噸以上。

and could reach several stories up with their long necks which came in handy for gathering enough food.

可以用長脖子伸長到好幾層樓高，方便收集足夠的食物。

After all, you can't grow this big without a lot of energy.

畢竟，你需要很多的能量才能長這麼大。

In fact, Brontosaurus ate about 45 kilograms of leaves, stems, and twigs a day.

事實上，雷龍一天大約吃 45 公斤的葉子、莖和小樹枝。

But they couldn't waste energy hunting around to find those veggies.

但是牠們不能浪費能量四處尋找那些蔬菜。

Instead they parked themselves in one spot for hours and used their long necks to graze up and down, stripping trees like a giant corn on the cob.

相反，牠們讓自己停在一個地方幾個小時，並用牠們的長脖子來上下吃草，把樹剝得像玉米棒上的大玉米。

And the more these animals sat around and ate, the bigger they became.

這些動物坐在這裡吃得越多，牠們就越大隻。

Tens of millions of years later, we see another bird-like dinosaur enter the stage.

幾千萬年後我們看到了另一種似鳥的恐龍進入這個發展時期。

Titanosaurs, the largest dinosaurs in history.

暴龍是歷史上最大的恐龍。

Dreadnoughtus, Patagotitan, and Argentinosaurus could stand over 20 meters long.

無畏龍、巴塔哥泰坦巨龍和阿根廷龍可以站立超過 20 公尺長。

But of course, their height couldn't save them from the asteroid strike.

但當然，牠們的身高無法拯救牠們脫離小行星撞擊。

And there's been nothing like them since, at least on land anyway.

從此以後再也沒有像恐龍一樣的生物，至少在陸地上沒有類似的。