20171010 独角鲸 最终版

您正在收听《大脑开窍》，我们以认真的态度探索好奇。

You're listening to Brains On, where we're serious about being curious.

《大脑开窍》部分资金由美国国家科学基金会赞助。

Brains On is supported in part by a grant from the National Science Foundation.

嘿。

Hey.

你收听《大脑开窍》，这意味着你对我们而言非常宝贵。

You listen to Brains On, so that means you have something really valuable to us.

你对节目的看法。

Your thoughts about the show.

我们正与美国国家科学基金会合作改进《大脑开窍》，希望能听到你的声音。

We're working with the National Science Foundation to make Brains On even better, we'd love to hear from you.

你通过什么方式收听？

How do you listen?

你为什么要收听？

Why do you listen?

你从节目中获得什么收获？

What are you taking away from the show?

我们想知道。

We want to know.

你可以通过在线填写简短问卷或报名参加家庭访谈来帮助我们。

You can really help us out by answering a short survey online or by signing up to be a part of family interviews.

作为感谢，你将获得一份很酷的惊喜礼物。

And you'll get a cool thank you surprise for helping us out.

直接访问brainson.org/supernova。

Just go to brainson.org/supernova.

那是brainson.org/supern0va。

That's brainson.org/supern0va.

感谢你的帮助，击个掌吧。

Thanks and high fives for the help.

让我们开始表演吧。

Let's start the show.

闭上眼睛仔细听。

Close your eyes and listen.

听。

Listen.

当你听到这些声音时，脑海中浮现出什么画面？

What are you picturing when you hear these sounds?

外星行星？

An alien planet?

或者是宇宙飞船降落，还是幽灵的舞会？

Or maybe a spaceship landing or a dance party for ghosts?

听起来像科幻小说，但这些都来自大自然的真实声音。

It sounds like science fiction, but these are real noises from nature.

那是北极的声音。

That is the sound of the Arctic.

你听到的是动物——髯海豹和独角鲸的声音。

Those are animals you're hearing, bearded seals and narwhals.

今天我们将带您前往北极，来回答来自俄勒冈州库斯湾的西尔维提出的这个问题。

And today we're taking you to the Arctic to answer this question from Sylvie in Coos Bay, Oregon.

我的问题是为什么独角鲸会长角？

My question is why do narwhals have horns?

不知道什么是独角鲸吗？

Don't know what a narwhal is?

对它那强大的角感到好奇吗？

Curious about its mighty horn?

那就继续听下去吧。

Well Keep listening.

您正在收听的是美国公共媒体的《Brains On》节目。

You're listening to Brains On from American Public Media.

我是莫莉·布鲁姆，今天的共同主持人是来自洛杉矶的莉娅和玛雅。

I'm Molly Bloom, and my cohost today are Leah and Maya from Los Angeles.

你好。

Hello.

嗨。

Hi.

非常感谢你们能来参加节目。

Well, thank you guys so much for being here.

今天我们非常兴奋，因为我们要讨论关于独角鲸的一切。

Today, we are excited because we are talking all about narwhals.

以防您之前没见过独角鲸，先来看看它们长什么样。

And just in case you haven't seen a narwhal before, here's what they look like.

它们是鲸鱼的一种。

They're a kind of whale.

它们身长与汽车相当，通常体重超过一吨。

They're about as long as a car, and they usually weigh more than a ton.

它们

They

有着斑驳的浅色皮肤，

have pale skin dappled with

上面有深灰色斑点。

dark gray spots.

但最显著的特征

But the feature that makes them most distinctive

是它们的角。

Is their horn.

你可能

You might have

见过独角鲸的图画或照片，看起来就像头上长着独角的鲸鱼。

seen a drawing or a picture of a narwhal that makes it look kind of like a whale with a single horn coming out of its head.

像独角兽一样。

Like unicorn.

对。

Right.

只是没有闪光、彩虹，也没有蹄子和腿。

But without the sparkles and rainbows or hooves and legs.

实际上，那根本就不是角。

And actually, it's not a horn at all.

那是长牙。

It's a tusk.

就像你在大象或海象身上看到的那样。

Just like you see on an elephant or a walrus.

而且长牙其实就是牙齿。

And tusks are teeth.

所以独角鲸的角只是一颗特别长的牙齿。

So the narwhal's horn is just a really long tooth.

而且它不是从独角鲸的额头长出来的。

And it's not coming out of the narwhal's forehead.

它是从独角鲸嘴里穿出，通过前唇的一个洞延伸出来的。

It's coming out of the narwhal's mouth and through a hole in its front lip.

与光滑的曲面不同，

Instead of a smooth curved surface, the

长牙实际上是螺旋状的。

tusk actually spirals.

如果你没见过独角鲸，可以访问我们的网站brainson.org，看看这些超酷海洋哺乳动物的照片和视频。

If you haven't seen a narwhal before, you can head to our website brainson.org to see some photos and videos of these very cool marine mammals.

Leah和Maya，你们第一次看到独角鲸照片时是什么感觉？

Leah and Maya, what did you first think when you saw a picture of a narwhal?

看起来挺酷的。

It looked pretty cool.

我当时还在想为什么它只有一根长牙。

And I was wondering why it only had one tusk.

我觉得我可能会称它为海里的独角兽，因为它看起来就像是从海里冒出来的独角兽。

I think I might have called it a unicorn of the sea because it looked like a unicorn that was coming out of the sea.

完全同意。

Totally.

它们看起来太酷了。

They are so cool looking.

那它们为什么会长这些长牙呢？

So why do they have these tusks?

只是为了装饰吗？

Are they just for decoration?

就像一种极端的唇部穿孔？

Like an extreme lip piercing?

还是说它们有实际用途？

Or do they have a purpose?

你觉得这些长牙是用来做什么的？

What do you think the tusks are used for?

我听说它们的长牙上有某种孔洞，可能用来感知温度变化。

I've heard they have some kind of holes in them that maybe detect change in warmth.

我觉得它们可能是用来破冰的，这样它们就能浮出水面呼吸。

I feel like they're for breaking through ice so they can get to surface to breathe out of the water.

幸运的是，我们这里有位专家能解答所有关于独角鲸的问题。

Well, we are lucky enough to have someone here who can answer all of our narwhal questions.

克里斯汀·莱德拉是西雅图华盛顿大学的海洋生物学家。

Kristen Lydra is a marine biologist at the University of Washington in Seattle.

你好，克里斯汀。

Hello, Kristen.

你好，莉娅。

Hi, Leah.

你好，玛雅。

Hi, Maya.

独角鲸是怎么长出这些角的？

How do narwhals get these horns?

或者我应该说长牙。

Or I should say tusks.

是啊。

Yeah.

独角鲸是怎么长出长牙的？

How do the narwhals get the tusks?

独角鲸并不是生来就有长牙的。

So narwhals are not born with their tusk.

无论是雄性还是雌性，出生时看起来都一样。

Both both boys and girls, when they're born, they look the same.

随着雄性幼鲸逐渐成熟，长牙会从上颚冒出并开始生长。

And slowly, as the young boys mature, the tusk erupts out of the out of the upper jaw and starts to grow.

而且长牙会持续生长很长时间。

And the tusk grows for quite a long time.

它可能需要生长十到十二年，直到那只年轻的雄性成长为成年雄性。

It can grow for for ten or twelve years to the point where that young male becomes an adult male.

那么为什么只有雄性有长牙，雌性没有呢？

So why do only males have the tusks, not female?

长牙基本上是用来炫耀的。

The tusk is basically for showing off.

如果你想想世界上其他动物，比如有浓密鬃毛的狮子，或者有巨大鹿角的不同鹿种，通常都是雄性。

And so, if you think about other animals across the world, like the lion that has a big mane or the, different deer that have big antlers, they're often males.

这些雄性会用那些花哨的附属物相互竞争，基本上就是决定谁是老大，或者谁应该赢得雌性的青睐。

And those males use those kind of fancy flashy appendages to compete with each other and basically decide who's the boss or who's, you know, who's the person that should get the girl.

所以我们认为独角鲸的长牙在科学上被称为性征，但本质上就是雄性用来帮助竞争和决定谁当老大的华丽装饰。

And so what we think is the narwhal tusk is is scientifically what we call a sexual trait, but it's basically something flashy that the boys have to help them compete and decide who's the boss.

最近有无人机拍摄到独角鲸用它们的牙做了一些有趣的事情。

A drone recently captured narwhals doing something interesting with their tusks.

是什么？

What was it?

是的，最近有一些影像资料流传出来，显示一只长牙独角鲸在水面游过鱼群时，头部来回摆动。

So, yeah, recently there was some footage that was distributed, of a narwhal with a tusk at the surface swimming through a school of fish, and the whale was moving its head back and forth.

看起来它可能是在用长牙搅动甚至击晕鱼群。

And it looked like it may have been using its tusk to either disturb or even possibly stun the fish.

这非常有趣。

And so, that was very interesting.

我想说我们绝对需要更多信息才能真正了解独角鲸是否这样使用长牙来捕鱼，但这就是科学的本质——学习新事物并探索它们。

I would say we definitely need more information to really understand if if narwhals use their tusk in that way for finding fish, but, that's what science is all about, learning new things and exploring them.

要知道，多年来关于独角鲸长牙的假说层出不穷，无论是用它来破冰、击剑，还是进行其他活动。

You know, there have been a lot of hypotheses about the tusk over the years, whether it's used to break ice or it's used to sword fight or, you know, do do other things.

而且我得说，这些假说大多缺乏有力证据支持。

And, I would say there's not a lot of evidence for any of those other hypotheses.

有观点认为长牙非常敏感，这或许是真的。

There's been some suggestions that it's, very sensitive and, that may be true.

就像你吃冰冷冰淇淋时，牙齿会感受到那种刺激一样。

If you think about your teeth when you eat cold ice cream, you often feel that on your teeth.

但这并不意味着长牙对生存至关重要，因为最关键的事实是：只有雄性独角鲸才长有这种长牙。

But it doesn't mean that the tusk is really what we would say critical for survival because the number one thing is that only the males or the boys have a tusk.

所有雌性独角鲸都没有长牙，但它们照样活得很好。

So all of the female narwhals that are swimming around out there have no tusk and they manage just fine.

它们能顺利觅食。

They're able to find food.

能够完成迁徙。

They're able to migrate.

可以生育并抚养幼崽。

They're able to give birth and raise their young.

所以我们认为长牙并非生存必需器官。

So we really don't think the tusk is something critical for survival.

除了长牙之外，它们还有其他牙齿吗？

Do they have other teeth besides the tusk?

实际上独角鲸口腔内没有其他牙齿。

Narwhals actually have no teeth inside their mouth.

所以如果你打开独角鲸的嘴，里面全是牙龈。

So if you open up the mouth of a narwhal, it's all gums.

实际上它们还有另一颗长牙嵌在头骨里，在极少数情况下会发育成第二根长牙，形成双长牙的独角鲸。

And they what they actually have, they have another long tooth that remains embedded inside the skull, and that's the that's the second tooth that will grow in the very rare case where you have the double tusked narwhal.

但除此之外，它们没有牙齿。

But otherwise, they have no teeth.

它们直接整个吞下猎物。

They just swallow swallow their prey whole.

独角鲸能活多久？

How long does a narwhal live?

根据记录，我们已知最长寿的独角鲸大约能活到100岁。

A narwhal, the oldest living narwhals that we have documented are about a 100 years old.

那真是相当长的寿命。

That's a very long time.

独角鲸和独角兽的神话有关联吗？如果有，是怎样的关联？

Are narwhals connected to the myth of unicorns and if so, how?

是的，这个问题问得好。

Yeah, great question.

独角鲸确实与独角兽神话有关。很久以前在维京时代，维京人会航行到格陵兰附近的北极海域，与因纽特人交易，将独角鲸的长牙带回欧洲。

So, narwhals are connected to the myth of unicorns and a long time ago in the Viking era, the Vikings would actually sail up to the Arctic to waters around Greenland and they would barter with the Inuit people and they would bring narwhal tusks back to Europe.

回到欧洲后，他们会编造关于这些长牙来历的故事——准确说是谎言——让人们愿意花大价钱购买。

And when they got back to Europe, they would tell stories or well basically lies about where those those tusks came from and make up stories that made people wanna pay a lot of money for them.

比如谎称这些长牙来自独角兽。

Like, for example, that the tusks came from unicorns.

所以人们非常想要这些长牙。

And so people, really wanted these tusks.

国王们会购买这些长牙，并用它们制作王座。

Kings would buy the tusks and make their thrones out of them.

直到十八世纪末，才有人站出来说，嘿。

It wasn't until the late seventeen hundreds when somebody basically came out and said, hey.

这些不是独角兽的角。

These aren't from unicorns.

这些是鲸鱼的牙齿。

These are from a whale.

就像一副好假牙，我们先暂时把牙齿放一边，关注一下我们的耳朵。

Like a nice set of dentures, we're going to put teeth aside for a minute and focus on our ears.

现在是神秘声音时间。

It's time for the mystery sound.

神秘声音。

Mystery sound.

来了。

Here it is.

好的。

Okay.

你们有什么猜测吗？

Do you guys have any guesses?

听起来像是海鸥的叫声？

It sounds like seagulls maybe?

听起来像是海滩，但仿佛有上千只海鸥。

It sounds it sounds like the beach but with like a thousand of seagulls.

不是真的有一千只。

Not like literally a thousand.

听起来像是有很多海鸥的海滩。

Sounds like a beach with a lot of seagulls.

是的。

Yes.

嗯，这是个绝妙的猜测。

Well, that is an excellent guess.

我们稍后会揭晓答案。

We will be back with the answer in just a bit.

好的，现在回到克里斯汀·莱德拉，了解更多关于独角鲸的信息。

Okay, now back to Kristen Leidra so we can learn some more about narwhals.

气候变化对独角鲸是有益还是有害呢？

Is the narwhals climate change helping them or affecting them in any way?

这是个好问题，科学家们正在研究这个问题。

That's a great question and that's something scientists are studying right now.

我们知道北极乃至全球正在发生巨大变化，这都是由气候变化引起的。

So we know that there are big changes happening across the Arctic and of course across the globe and that is due to climate change.

北极发生的一些最重大的变化可能会影响独角鲸，比如海冰正在消失。

And some of the biggest things that happen in the Arctic that could affect narwhals are the fact that the sea ice is disappearing.

当北极发生这种情况时，整个生态系统都会改变。

And then when that happens in the Arctic, it changes the whole ecosystem.

海水变得更温暖了。

The water gets warmer.

洋流会发生变化，这会影响到独角鲸所食鱼类的分布位置。

The currents can change, it can affect where the fish are that narwhals eat.

我们尚未完全理解气候变化对独角鲸意味着什么，但有一点可以确定，它们对冰层环境有着独特的适应性。

And we don't completely understand what the climate change will mean for narwhals, but one thing we know for certain is that narwhals are very uniquely adapted to be in the ice.

它们是鲸类中最适应冰层生活的物种之一。

They're some of the kind of best they're the whales that do the best in the ice.

因此如果失去冰层环境，很可能会对它们产生负面影响。

And so if you take that away, it's likely to have some negative effects.

但目前我们还未完全理解所有这些影响。

But we don't completely understand all of those yet.

独角鲸如何交流？

How do narwhals communicate?

独角鲸通过水下声波进行交流。

So narwhals use sound, underwater sound, to communicate.

基本上它们会发出高频咔嗒声，类似于声纳或潜水艇使用的技术。

And, basically, what they do is they're able to send off very high frequency clicks, kind of like sonar, like an underwater submarine.

这些声波在水下遇到物体会反射回来，独角鲸接收这些信号后，就能通过声音构建出水下环境的图像。

And those clicks bounce off of different objects underwater, and then they come back to the narwhal, and they receive the signals, and they're able to basically use the sound to make a picture of what's underwater.

我们知道独角鲸使用回声定位来寻找鱼类，或是探测冰层中的呼吸孔。

So we know that narwhals use sound that's called echolocation to basically find fish or to, look for holes in the ice where they come up to breathe.

独角鲸还会发出哨声、吱吱声等有趣的水下噪音来相互交流。

And narwhals will also use sound like they'll make whistles and squeaks and kind of kind of funny noises basically underwater to communicate with one another.

所以有点像海豚或蝙蝠？

So sort of like a dolphin or a bat?

完全像海豚或蝙蝠。

Exactly like a dolphin or a bat.

那真的很酷。

That's really cool.

确实很酷。

It is so cool.

我要告诉你一件事。

And I'll tell you one thing.

我们最近发现。

We we recently found out.

我们一直在研究独角鲸如何在水下利用声音，我们认为独角鲸是整个动物界中利用声音的物种之一，它们基本上拥有最精确的声呐定位能力。

We've been doing studies of how narwhals use sound underwater, and we think that the narwhals are are one of the species across the whole animal kingdom that use sound that have basically the most precise ability to use sound to see.

你可以想象一下，就像一盏可调节的手电筒。

So you can kind of imagine, like, an adjustable flashlight.

你知道，如果你有一把手电筒，你可以旋转它，它会发出很宽的光束。

You know, you have if you have a flashlight, you can turn it, and it will make a really wide beam.

它能照亮你面前的一大片区域。

It'll light up a whole bunch of stuff in front of you.

然后你可以朝另一个方向旋转，它会发出像激光一样的超窄光束，将光线精确指向某个位置。

And then you can turn it the other way, and it makes a super narrow beam like a laser, and it points the light in a very precise place.

我们认为独角鲸基本上能在水下用声音做到这一点。

Well, we think narwhals are basically able to do that with sound but underwater.

谢谢你今天能来，克里斯汀。

Thanks for being here today, Kristen.

是的。

Yes.

谢谢。

Thank you.

谢谢你们两位。

Thanks to both of you.

你们表现得非常棒。

You were great.

很高兴能和你们交谈。

It was a pleasure to talk to you.

我们正在制作一期关于生物节律如何维持我们睡眠-觉醒周期的节目，想听听大家的看法。

We're working on an episode coming up about the biological rhythms that keep us on a sleep wake cycle, and we want to hear from you.

你认为做晨型人好还是夜猫子好？为什么？

Do you think it's better to be a morning person or a night person, and why?

请将你的回答通过邮件发送至hello@brainson.org。

Email your answers to us at hello@brainson.org.

我们会在接下来的节目中选取部分内容，你也可以发送

We'll include some of them in our upcoming episode, and you can send

神秘声音和图画

Mystery sounds Drawings

以及击掌鼓励

and high fives

发送到同一个邮箱地址：hello@brainzon.org。

to that same email address, hello@brainzon.org.

这就是米卡发送这个问题的地方。

That's where Mika sent this question.

水有味道吗？

Does water have a taste?

我们将在节目中的'荣誉时刻'环节回答米卡这个令人垂涎的问题，并公布最新入选'大脑荣誉榜'的名单。

We'll answer Mika's mouth watering question during our moment of plus the most recent group to be added to the brains honor roll.

请坚持听到节目最后，答案即将揭晓。

Stick around to the end of the show to hear it all.

在《但是为什么》节目中，我们解答你提出的难题。

On But Why, we tackle your tough questions.

如果做了被告知不能做的事却永远不告诉任何人，这样可以吗？

Is it okay to do something you're told not to do and then never tell anybody?

为什么人老了就必须要死？

Why do people have to die when they get too old?

为什么钱这么重要？

Why is money so important?

在《但是为什么》这档为好奇孩子打造的播客中，我们一起探索那些没有简单答案的问题。

Exploring questions with no easy answers on But Why, a podcast for curious kids.

头脑风暴！

Brainstorm!

您正在收听的是美国公共媒体出品的《大脑上线》。

You're listening to Brains On from American Public Media.

我是莉娅。

I'm Leah.

我是玛雅。

And I'm Maya.

我是莫莉。

And I'm Molly.

在我们深入了解动物牙齿的趣闻之前，先来重温一下那个神秘的声音。

Before we bite into some cool facts about animal teeth, we're going to go back to that mystery sound.

大家准备好再听一遍了吗？

You guys ready to hear it one more time?

是的。

Yes.

嗯。

Mhmm.

好的。

Alright.

让我们听听看。

Let's hear it.

好的。

Okay.

你们又听到了一遍。

So you heard it again.

有什么新想法吗？

Any new thoughts?

不。

No.

但听起来有点怪，不过更有趣。

But it sounded weird, a little more, like, interesting.

有些部分我没听清楚。

There's some parts that I couldn't make out in it.

所以我决定坚持我们现有的猜测。

So I'm just gonna stick with the guess that we have.

是的。

Yes.

显然是在一片超大沙滩上的海鸥。

Seagull in a really big beach, apparently.

一片超大沙滩上的海鸥。

Seagull in a really big beach.

猜得真棒。

Excellent guess.

现在公布答案，来自康涅狄格州沃灵福德的萨米。

Well, here with the answer is Sammy from Wallingford, Connecticut.

那是蓝喉鸟的声音。

That was a sound of blue gorails.

我叫萨米，我特别喜欢那些白鲸。

And my name is Sammy, and I really like those beluga whales.

它们太可爱了。

They are adorable.

它们说话非常清晰。

They speak so clearly.

它们能在水下听到声音。

They can hear underwater.

它们可以是非常可爱的动物。

They can be a very cute animal.

谢谢。

Thank you.

所以是白鲸啊。

So beluga whales.

哇哦。

Woah.

你们之前听过鲸鱼的声音吗？

Have you guys ever heard a whale before?

听过。

Yes.

嗯哼。

Mhmm.

但之前听起来不太像这样对吧？

But they didn't quite sound like that before?

不像。

No.

不像。

No.

所以背景里的那些人，他们当时在康涅狄格州米斯蒂克的水族馆。

So all those people in the background, they were at the aquarium in Mystic, Connecticut.

独角鲸和白鲸不是近亲吗？

Aren't narwhals and belugas cousins?

这个问题问得好。

That is a great question.

是的。

Yes.

它们确实是。

They are actually.

独角鲸其实是鲸类的一种。

They're narwhals are a type of whale.

你们听过《小白鲸》这首歌吗？

Have you guys heard the song Baby Beluga?

哦，当然。

Oh, yeah.

听过。

Yes.

可惜拉菲不会模仿白鲸的叫声，所以在这个场景下没什么用。

Unfortunately, Raffy doesn't really make the sound of the beluga whale, so it wasn't really useful in this circumstance.

是啊。

Yeah.

我的大脑开机了。

My brain's on.

独角鲸独特的长牙并非唯一酷炫的牙齿种类。

Narwhal's distinctive tusk is not the only kind of cool tooth out there.

世界上有许多不同种类、功能各异的牙齿。

There are lots of different kinds of teeth with very different uses.

为了了解更多，我们要去'疯狂艾迪的牙齿大卖场'看看。

And to find out more, we're going to take a trip to Crazy Eddie's Tooth Emporium.

你好？

Hello?

艾迪，来客人了。

Eddie, we have a customer.

我看得见有客人来了，艾迪。

I can see we have a customer, Eddie.

嗨。

Hi.

我想买人生第一颗牙齿。

I'm looking to get my first tooth.

等等。

Wait.

你们俩都叫艾迪吗？

Are you both named Eddie?

我们是双胞胎。

We're twins.

妈妈懒得记两个名字。

Mom didn't wanna memorize two names.

欢迎来到疯狂艾迪的牙齿大世界。

Welcome to Crazy Eddie's Tooth Emporium.

牙齿就是我们的真理。

Tooth is our truth.

我们对牙齿痴迷不已。

We're bonkers for chompers.

只要是脸上的东西，我们这里应有尽有。

If it goes in your face, we're the place.

一站式满足您所有咀嚼、啃咬、磨牙、捣碎的需求。

A one stop shop for all your chomping, chewing, gnashing, mashing needs.

自从四亿年前动物首次进化出最早的牙齿结构以来，我们家族就一直提供牙齿服务。

Our family's been providing teeth since animals first evolved the earliest teeth like structures some 400,000,000 years ago.

呃，我只想要一颗普通的牙齿。

Well, I just want a simple tooth.

不要太花哨的。

Nothing too flashy.

这是我的第一颗牙，

It's my first one,

简单是吧？要知道我们伟大的曾曾曾...（我忘记有多少个'曾'了）

so Simple, Well, when our great, great, great, great, great, great, oh, I forget how many greats.

32代？也许？

32, maybe?

老祖宗撒迪厄斯·牙本质在四亿年前创办了这家企业。

Grandpappy, Thaddeus Dentine, started this business four hundred million years ago.

牙齿曾经非常简单。

Teeth were real simple.

看看这个宝贝。

Check this baby out.

那是牙齿吗？

That's a tooth?

其中之一

One of

已知最早的牙齿之一，其实是一种齿板，来自一种鱼类。

the first known teeth, sort of a tooth plate, really, from a fish, I believe.

一种叫做罗氏鱼的古老盾皮鱼。

An ancient placoderm called a romendina.

看起来更像带刺的石头或砂纸之类的东西。

Looks more like a spiky rock or sandpaper or something.

嗯，这不是你我认知中的牙齿。

Well, it's not what you and I think of as a tooth.

在我们拥有牙齿之前，只有表皮附属物。

Before we had teeth, there were just dermal appendages.

这些是类似鳞片的坚硬结构，像牙齿一样覆盖在古鱼体表如同盔甲。

These were scale like structures that were hard like teeth and covered the bodies of ancient fish like armor.

对防护很有效，但不适合进食。

Great for protection, but not eating.

最终，鱼类进化出将这些带刺鳞片长在嘴里的特征。

Eventually, fish evolved to have these spiky scales in their mouths.

天啊，那些锯齿状的牙齿确实帮助那些鱼类捕捉并牢牢咬住猎物。

Boy, did those toothy plates help those fish catch and hold on to prey.

明白了。

Gotcha.

缺点是咬第一口后就很难再咀嚼了。

The downside was you couldn't really chew after your first bite.

也许你想要点更实用的东西？

Perhaps you want something a little more useful?

当然。

Sure.

啊，没错。

Ah, yes.

就是这个，巨齿鲨的牙齿。

Here it is, the megalodon tooth.

什么是巨齿鲨？

What's a megalodon?

什么是巨齿鲨？

What's a megalodon?

巨齿鲨是远古时期的巨型鲨鱼。

Megalodons are ancient monstrous sharks.

它们生活在2300万年前，约200万年前灭绝，体长可达60到80英尺。

They lived twenty three million years ago, going extinct about two million years ago, and grew to be anywhere from 60 to 80 feet long.

它们的牙齿巨大，有些甚至有人类手掌那么大。

And their teeth were huge, some as big as a human hand.

它们锋利、尖锐，边缘参差不齐。

They were sharp, pointy, and jaggedy edgety.

他的意思是锯齿状的。

He means serrated.

对，就是那样。

Yeah, that.

天哪，它们能咬进猎物并撕下大块肉来。

And man, oh man, could they bite into and tear big chunks from their prey.

它们甚至能切断骨头。

They could even cut through bone.

我觉得这颗牙不适合我。

I don't think that's a tooth for me.

它甚至塞不进我的嘴。

It won't even fit in my mouth.

对你来说牙太多了，也许你更适合像两亿年前的迪佩迪鱼那样碾碎小壳类蜗牛或蛤蜊。

Too much tooth for you, Maybe you're into crushing smaller shelled snails or clams like the ancient 200,000,000 year old dipedium fish.

它有个高瘦的身体，看起来像个餐盘，用扁平如鹅卵石的牙齿和强壮的颌骨碾碎外壳，吃掉里面美味的肉。

It had a tall thin body that sort of looked like a dinner plate and used its flat, almost pebble like teeth and strong jaws to pulverize shells and eat the tasty insides.

看看这个。

Check it out.

很酷，但我不想吃壳类和蜗牛。

Cool, but I don't wanna eat shells and snails.

对法式蜗牛不感兴趣。

Not into escargot.

我明白了。

I understand.

这里，我们有一些爬行动物的牙齿。

Here, we have reptile teeth.

这些动物在进化过程中，牙齿逐渐分化。

When these animals evolved, they developed more differentiated teeth.

换句话说，它们口腔里的牙齿并不完全相同。

In other words, not all the teeth in their mouths were the same.

有些牙齿较小，有些则较大。

Some were small and some were larger.

我们称之为异齿型。

We call this heterodonti.

'异'代表不同，'齿'就是牙齿。

Hetero for different and denti for teeth.

与之相对的是同齿型。

As opposed to homodonti.

'同'表示相同，'齿'依然指牙齿。

Homo meaning same and denti still meaning teeth.

看看这条蛇的毒牙。

Get a load of the snake fang.

有了它，你就能通过注射毒液捕食比自己大十倍的猎物。

With this, you can take on prey 10 times your size by injecting them with venom.

这些小家伙又细又尖，毒液导管将毒牙尖端与毒腺相连，让你随时准备好享用下一餐。

These babies are slender and sharp, and a venom canal connects the tip of the fang to the venom gland, so you're always ready for your next meal.

嗯，嗯，嗯。

Nom, nom, nom.

但我还是个孩子。

But I'm a kid.

我没有毒腺。

I don't have a venom gland.

对。

Right.

也许你的牙齿有多功能性？

Maybe versatility in your teeth?

好吧。

Okay.

这里是哺乳动物区。

Here's the mammal section.

哺乳动物是温血动物，所以需要摄入大量卡路里来保持体温。

Mammals are warm blooded, so they've gotta eat a lot of calories to keep warm.