It affected the young animal's front legs, which became hyperextended.

这种疾病影响了幼崽的，使腕关节过度伸展。

All birds have two legs and two arms; but these arms are not like ours.

所有的鸟儿，都有两个后，两个。但是鸟儿的， 跟我们人类的不一样。

The first was its trio of claws extending from each hand.

第一件就是每个伸出的三个爪子。

Whereas with pterosaurs, with this strategy, you're focusing it into one area and really use it both ways.

所以，翼龙的飞行只会使用。

Eventually, their front limbs became flippers and their hind limbs became weak and unnecessary.

最终，它们的变成了鳍状，而它们的后变得虚和多余。

And they were almost right. Longer front legs and larger toe pads indeed helped.

他们的想法基本上是对的。、垫大确实有帮助。

We call them wings, and the birds use them for flying.

我们管鸟儿的叫" 翅膀" ，鸟儿就是用翅膀来飞翔的。

Its small arms are useless in the water, leaving it to rely on its two powerful legs.

它短小的在水中没有用，只能靠两条有力的后腿。

Its powerful arm muscles are composed of 80% fast-twitch fiber, a third more than humans.

它强壮的肌肉中百分之八十是快缩肌纤维，比人类的多三分之一。

Technically, two-toed sloths should be really called two-fingered sloths because the difference is only their front limbs.

从技术上讲，二树懒应该被称为二指树懒，因为它们的区别只是。

Well, the arms are kind of small.

它的的确很小。

What you can see is that large toe pads and strong front legs give some lizards a tighter grip.

你可以看的是，大的护和强壮的使一些蜥蜴抓握牢。

Led by his super sensitive nose, his long limbs carry him many miles a day in search of carrion.

凭借极度敏感的嗅觉和的，短面熊为了寻找腐肉能一天行进数英里。

The shape of the creature's hands and forelimbs suggest it was a skillful and powerful digger, scientists say.

科学家说，这种生物的手和的形状表明它是一种熟练而有力的挖掘者。

She has long, strong front legs to help her climb around for food 20 metres up in the canopy.

它的又又有力，可以帮助它在 20 米高的树冠上四处攀爬觅食。

As he rips back, he rips an enormous chunk of flesh from the underside of the arm.

它往后拽时，从其下侧拽下来相当大一块肉。

Although the arms of Albertosaurus were small compared to its overall body size, they were still packed in muscle.

尽管阿尔伯特龙的与体型相比很小，它们也有发达的肌肉。

It had, relative to size also comparing with T-Rex, its arm appeared larger.

它的按与身体比例来说比霸王龙的要大。

Utahraptor will usually grasp its prey with its arms and use its leg claws to slash at its victim.

犹他盗龙通常会用抓住猎物，然后用它的脚爪划割猎物。

You see, it is hard for bears to run down hill, because their hind legs are longer than their front ones.

你知道的，熊很难跑下山，因为它们的后比得多。