动物死后发生的每件事都会销毁信息，这就是最后剩不下什么的原因。

But think of the luck that we have to have simply to find it.

其实我们能找到就算够幸运的了。

They began to study the evidence to try and understand what had caused the gash and puncture wounds in the bones.

他们开始研究证据，试图了解这些骨头上的沟痕和穿孔是如何形成的。

What does the scratches on the leg bone of a dinosaur mean?Are they tooth marks, are they claw marks?

这些恐龙腿骨上的划痕意味着什么呢？是牙印还是爪子印？

That is the first question.

这是第一个问题。

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But once we look closer we start to understand really what a tooth mark looks like, there's a certain characteristic to it.

但一旦我们更进一步地观察，我们会开始懂得牙印看起来像什么，有一定的特征。

Then the question becomes: "How can we figure out who made that tooth mark?"

接下来的问题就是：“我们怎么知道到底是谁留下牙印的呢？”

Obviously, we need to know who're the potential perpetrator, who else was living in the environment, who was potentially available to, if you will, commit this crime.

显然，我们得先确定谁是潜在的行凶者，还有谁在这种环境里生活，谁有可能犯下这样的“罪行”。

Then, a clue.

有一条线索。

Mixed in among the various herbivore bones was a nearly complete skeleton of a monstrous looking predator - Ceratosaurus.

在各类植食性恐龙骨头之中有一付几乎是完整的骨架，看上去怪物般肉食性动物：角鼻龙。

He stood about 4 meters tall and 7 meters long.

它大概有4米高，7米长。

Compared to later dinosaurs like Tyrannosaurus-Rex, he was smaller.

跟晚些时候的恐龙比如霸王龙相比，它要小一些。

One feature easily distinguishes this meat eater from others - a nose horn.

一个特征轻易地将这个食肉者与其它的区分开来：鼻部的角。

The name Ceratosaurus means horned lizard.

角鼻龙原意就是长角的蜥蜴。

It was the first dinosaur found that had a horn on its nose.

它是人们发现的第一个鼻部长角的恐龙。

It wasn't a cone-shaped horn.It was actually a sort of flat blade shape.

它的角不是锥形,实际上是扁平的刃状角。

They're not for a combat at all.

这种角完全不是用来战斗的。

And if we were looking into modern world for an equivalent, we might look at something like the crest on the top of the head of a rooster.

要是在现代世界给这种角找个对应物的话估计会更像公鸡头上的鸡冠子。

Along with its unique skull design, Ceratosaurus has another feature that distinguishes it from other predators: four fingers on each hand.

在头骨的独特设计之外角鼻龙还有一个和其它掠食者不同特点：它的前肢各有四只手指。

One thing that's unusual when we look at Ceratosaurus is that it's got seemingly extra fingers compared to other of these predatory dinosaurs which usually have basically three fingers on each hand.

我们能在角鼻龙身上注意到一个不寻常的特征与其它的掠食性恐龙相比它要多出一个手指而一般的掠食恐龙只有三只手指。

Ceratosaurus has a forth.

角鼻龙有第四只手指。