Oh hey guys, you caught us on our lunch break!
Squeaks and I just stepped out of the lab to have a little snack … Well, at least
I’m having a snack.
And since Squeaks doesn’t have to eat like I do, I was just explaining to him what teeth
People have different kinds of teeth. I have molars in the back of my mouth that help me
grind up vegetables and other things.
But I also have pointed canine teeth so I can tear through things like meat. Being able
to eat different kinds of food is really important, to help you stay healthy.
Other animals have different kinds of teeth, too. But while they’re all super-useful,
some of them can seem a little strange.
Like, we all know sharks have sharp teeth.
But did you know many sharks have 5 rows of teeth? Sometimes even more!
A shark can go through thousands of teeth in a lifetime!
That’s because, unlike us, shark’s teeth aren’t rooted in bone.
Instead, their jaws are made of something softer, called cartilage — that’s the same
flexible stuff that you have, in your ears, or in the tip of your nose.
Since shark’s teeth sit in this soft cartilage, they can lose them pretty easily — especially
considering how they eat!
Sharks feed by biting down hard on their prey — like seals, or other fish — and they shake
them from side to side with a lot of force.
This can make their teeth come loose or even fall out, so they need to be able to replace
Luckily for them, they have these rows of new teeth right behind the last ones, just
waiting to move up. When a shark loses a tooth, it’s replaced with another one in just one
or two days.
Other predators have different kinds of teeth for catching food.
Vipers, for example, are a kind of snake, and they have fangs.
平时 它将毒牙收起来藏在上颚 如此
When a snake is resting, these special teeth fold up inside its mouth, so that they’re
out of the way.
但是 当毒蛇捕猎的时候 比如说 捕猎老鼠
But when the snake bites its prey, like, say, a rat –
Squeaks: [worriedly, frantically squeaks]
杰西： 稍安勿躁 不是吃你 不是你这种机械老鼠 是真真正正的老鼠哦
Jessi: Oh, no no no, not you Squeaks! No a mechanical one, a real one!
当毒蛇咬住老鼠时 毒牙就像针一样刺入老鼠体内 如此 毒囊里的毒液就通过
When it bites into a real rat, these teeth act like needles. Toxic venom then travels
from the snake’s mouth through the hollow fangs and directly into the prey.
但是 牙齿不仅仅是捕食的工具 其他动物的牙齿就有与众不同的作用
But teeth aren’t just for eating! Other animals use them for different reasons.
For instance, did you know tusks are teeth?
Walruses have tusks up to a meter long, and they keep growing throughout their whole life.
Male walruses sometimes use their tusks like swords, to fight with other males.
But, both males and females use their tusks for other reasons, too.
例如 当它们在冰面下游泳时 它们就可以用獠牙破冰
Like, when they’re swimming under the ice, they can use them to poke holes in the ice
so they can come to the surface to breathe.
And they can even use their tusks to pull their big, heavy bodies out of the water.
But there’s probably one animal that’s more famous than any other for its unusual
Squeaks: [excitedly squeaks]
Jessi: That’s right! That’s right! I’m talking about beavers!
Beavers are well-known for their oversized incisors.
海狸的门牙一直在长 因此 它需要不停地磨牙
These teeth never stop growing, so beavers are constantly trying to wear them down by
chewing on wood.
You might think that chewing on wood all of the time would ruin the beavers’ teeth.
But the front side of their teeth actually has iron in it!
Iron is the same stuff that they use to make really strong metals. And it not only makes
海狸的牙齿变得坚硬无比 还让海狸拥有了独一无二的铁锈色牙齿 就像
beavers’ teeth extra tough, it also gives them their unique, rusty orange color — kind
of like the rust you might see on an old car or bicycle.
So it’s this extra strength that makes it possible for beavers to bite through wood,
for as long as they want to.
No wonder they can stay so busy, those busy beavers!
说到忙 我们得去工作了 谢谢各位
Speaking of busy, we have to get back to work, but thanks for sharing our lunch time with