Feathers are some of the most remarkable things ever made by an animal.
羽毛是动物身上几件最奇妙的东西之一。
They are gorgeous in their complexity, delicate in their construction,
羽毛构造极为复杂，精细，让人惊叹，
and yet strong enough to hold a bird thousands of feet in the air.
而且还够强壮，可以让鸟类飞上数千尺的高空。
Like all things in nature, feathers evolved over millions of years into their modern form.
就像自然界的其它东西一样，羽毛经历了几百万年，才进化到现在的形式。
It could be hard to imagine how this could have happened.
我们可能很难想像这是怎么发生的。
After all, what did the intermediate forms look like?
那么中间那过度的形式到底是什么样子的呢？
What good is half a wing, festooned with half-feathers?
这种在翅膀上覆盖了羽毛的结构究竟好在哪里呢？
Thanks to science, we now know that birds are living dinosaurs.
得益于科学研究，我们现在了解到鸟类就像是还活着的恐龙。
You can see the kinship in their skeletons.
你可以看到它们骨架非常相似。
Certain dinosaurs share some anatomical details with birds found in no other animals, such as wish bones.
某些恐龙和鸟类一样，都有一些在动物界独一无二的身体结构，比如说叉骨。
And in the late 1990s, paleontologists started digging up some compelling support for that idea:
在1990年代末期，古生物学家开始挖掘出一些有力的证据：
dinosaurs with bits of feathers still preserved on their bodies.
有些恐龙身上仍旧保有羽毛。
Since then, scientists have found dozens of species of dinosaurs with remnants of feathers.
在那之后，科学家发现许多种类的恐龙身上都有残存的羽毛。
Some were as small as pigeons, and some were the size of a school bus.
有些像鸽子一样小，有些则跟校车一样大。
If you look at how they are related on a family tree, the evolution of feathers doesn't seem quite so impossible.
如果你观察一下它们在系谱图上的关系，那么要进化出羽毛并不是那么不可能。
The most distant feathered relatives of birds had straight feathers that looked like wires.
鸟类最早的有羽毛的祖先，是有一种像电线一般的直条羽毛。
Then these wires split apart, producing simple branches.
后来这些电线开始分叉，产生比较小的分支。
In many dinosaur lineages, these simple feathers evolved into more intricate ones, including some that we see today on birds.
在许多恐龙的世系中，这些简单的羽毛进化成更加复杂的样子，其中就包括许多我们今天在鸟类身上看到的那种羽毛。
At the same time, the feathers spread across the bodies of dinosaurs,
同时，羽毛也开始遍布恐龙的全身，
turning from sparse patches of fuzz into dense plumage, which even extended down to their legs.
从零散的小块细毛演变为浓密的全身羽毛，甚至还长到脚上。

A few fossils even preserved some of the molecules that give feathers color.
少数的化石甚至保存了一些让羽毛显现出不同颜色的分子。
They reveal a beautiful range of colors: glossy, dark plumage, reminiscent of crows,
这些分子显现出一系列漂亮的颜色：光亮、深色的羽毛，让人想起乌鸦；
alternating strips of black and white, or splashes of bright red.
或是黑白相间的条纹，还有亮红色的色斑。
Some dinosaurs had high crests on their heads, and others had long, dramatic tail feathers.
有些恐龙头上有高高的冠羽，而有的则是有着相当长的尾羽。
Now, none of these dinosaurs could use their feathers to fly
但是，这些恐龙没有一只能够靠羽毛飞翔，
their arms were too short and the rest of their bodies were far too heavy.
它们的手臂太短，而身体其它部分又太重。
But, birds don't just use feathers to fly.
但是，鸟类不只是利用羽毛来飞翔。
A woodcock uses feathers to blend in perfectly with its forest backdrop.
丘鹬会用羽毛把自己隐藏于树丛的背景中。
An ostrich stretches its wings over its nest to shade its young.
驼鸟则会伸出它的翅膀来盖住巢穴，来保护它的幼鸟。
A peacock displays its magnificent tail feathers to attract peahens.
孔雀用它华丽的尾羽来吸引异性。
Feathers could have served these functions for dinosaurs too.
羽毛在恐龙身上也可能有这些功能。
Exactly how feathered dinosaurs took flight is still a bit of a mystery.
至于有羽毛的恐龙到底是如何开始飞翔的，这仍然还是个谜。
But if a small-feathered dinosaur flapped its arms as it ran up an incline,
但是如果羽毛细小的恐龙在爬坡时挥动它的手臂，
its feathers would have provided extra lift to help it run faster.
那么它的羽毛还是可以提供一些向上的力量，让它跑得更快。
This accident of physics might have led to the evolution of longer dinosaur arms,
这项物理的意外收获，可能导致进化出更长的手臂和羽毛。
which would let them run faster and even leap short distances through the air.
这会让它们跑得更快，甚至可以跳跃制空一小段。
Eventually, their arms stretched out into wings.
最后，它们的手臂进化成翅膀。
Only then, perhaps 50 million years after the first wiry feathers evolved, did feathers lift those dinosaurs into the sky.
只有到这时候，大约是第一只有羽毛的恐龙出现的五千万年后，羽毛才让恐龙在天空翱翔。