With the breaking up of the continents, the oceans moved closer to what is now North America, causing a dramatic increase in rain.

随着大陆的分离，海洋愈发靠近如今的北美洲，导致降水的急剧增加。

The herd is forced to the edge of the river.But they're unable to cross, so they have to make a stand.

角龙群被逼到了河边。但是它们无法通过所以只能停下来。

They lower their head and thrust their nasal horns towards the predator.

它们低下头，朝掠食者扬起它们的鼻角。

The Albertosaurus pace back and forth, probing for any weakness in their defense.

阿尔伯特龙前后踱步，寻找它们的防御中的薄弱部分。

As they circle, they take turns making mock charges in the hopes of panicking the group.

它们一边转着，不时轮流作势进攻希望能让整群恐龙惊慌。

They get their chance when one of the herd members breaks ranks and runs.

角龙群里有一头脱离群体开始逃跑，它们的机会随之而来。

The Pachyrhinosaurus herds were made up of a few dominant males and a harem of females and their children.

肿鼻角龙群由几头处于统治地位的雄恐龙一群妻妾和它们的孩子构成。

Albertosaurus live on instinct.The moment that Pachy breaks ranks and runs for it, the predators zero in on him and give chase.

阿尔伯特龙靠本能生存。那头肿鼻角龙离队逃跑的那一刻，掠食者就瞄准它进行追逐。

The Albertosaurus knows that separated from the herd, this Pachyrhinosaurus does not stand a chance of defending himself.It's the old adage, divide and conquer.

阿尔伯特龙知道这头肿鼻角龙离开了群体，就完全没有机会进行自我防御。老话说分割敌人，各个击破。

The Pachyrhinosaurus frill was almost 7 centimeters thick and made of solid bone.

肿鼻角龙的褶皱几乎有七厘米厚由坚硬的骨头构成。

As he turns, the jaws of the Albertosaurus snap closed on the side of his frill, and broken teeth fly into the air.

它转身之时，阿尔伯特龙的双颌咬住了它褶皱的侧面，碎裂的牙齿飞向了空中。

The Pachy lowers his head and hopes to ram the Albertosaurus with his long nose.

肿鼻角龙低下头希望能用它的长鼻子撞到阿尔伯特龙。

The Pachyrhinosaurus could regrow its horn if it broke.

如果肿鼻角龙的角断掉的话还能重新长出来。

One of the weaknesses of Albertosaurus is that its relatively lightly built.

阿尔伯特龙的一个弱点就是它的重量相对较轻。

Now looking at their size, that may seem hard to believe, but when you look at their skeletal design you'll see that their bones are hollow.

看到它们的体型会觉得这很难相信，不过要是看到它们骨骼的构成就会知道它们的骨头是中空的。

These hollow bones are rigid and strong, but they are very verylight.So if the Pachy gets lucky and hits a bone, it could break it without really any problem.

这种空心骨头很硬、强度很大，但它们非常非常轻。所以要肿鼻角龙运气好撞到骨头，毫无疑问会将其折断。

And this would not only take the Albertosaurus out of the fight, it could very well end its life.

这不仅会让阿尔伯特龙退出战斗，还很可能会让它丧命。

The Pachyrhinosaurus had a low center of gravity.

肿鼻角龙的重心比较低。

This allowed it to pivot quickly to keep its horn and protective frill facing an attacker.

这样它们能快速转身，让它的角和保护性褶皱对着攻击者。