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为什么人类没有长出触须?

Why Don’t Humans Have Whiskers?

你可能有伐木工人一样的大胡子 或者有铅笔般粗细的小胡子
Whether you’ve got a big ol’ lumberjack beard or a pencil-thin mustache,
你可能会把长在脸上的毛发称为“触须”
if you have facial hair, you might refer to it as your “whiskers.”
但它们并不是
But that is not what they are.
实际上 人类是不长触须的
The fact is, humans don’t have whiskers.
猫或狗长的才是真正的触须 它们比人类的面部毛发
True whiskers—like those on your dog or cat—are far more special
更加特别
than any human facial hair.
触须非常灵敏 能帮助动物捕食 感受风向
Whiskers are acutely sensitive and can help creatures hunt, sense the direction of the wind,
以及夜间出行
and find their way around in the dark.
事实上 这些触须作用很大 几乎所有的哺乳动物都有触须……
In fact, they are so useful, nearly all mammals have them…
我们(人类)却是个例外
we’re just one of the rare exceptions.
那么 触须和你下巴上的胡茬 到底有什么不同呢?
So, what makes whiskers different from the stubble on your chin?
触须就是科学家所说的“触须”
Well, whiskers are what scientists call vibrissae.
它们和普通毛发相似 都由相同的蛋白质和角蛋白构成
And they are similar to regular hair … they’re made out of the same protein, keratin.
但是触须通常更粗 更硬 更加重要
But whiskers are usually thicker, stiffer, and more importantly, they grow out of
它们生长的毛囊和人类毛发的毛囊截然不同
completely different kinds of follicles than your hairs do.
触须生长的毛囊在深层皮肤 周围环绕着血块
The follicles for vibrissae are deep in the skin, and they’re surrounded by pockets
这些血块和神经紧密相连
of blood, which are connected to nerves.
研究者认为 这些血块有助于放大来自触须的振动
Researchers think that these pockets of blood help amplify any vibrations that come through
使得触须极其敏感
the hairs to help make them extra-sensitive to touch.
当然 神经连接着大脑 大脑内部包含感觉皮质区
And the nerves, of course, lead up to the brain, where huge sections of the somatosensory
很大一部分的感觉皮质区负责分析
cortex are devoted to making sense of all the tactile information
触须接收的触感信息
that the whiskers are picking up.
动物的身体上遍布触须 但最常见的
Now, whiskers can be found anywhere on an animal’s body, but the most common spot
是脸上的触须 尤其是长在嘴边或眼睛周围的一般把它们分成两大类
is on the face, especially around the mouth or eyes, where they come in two main types.
我们通常看作“络腮胡”的长触须被称作“大触须”
The long hairs we usually think of as “whiskers” are called macrovibrissae,
动物们能任意摆动它们
and they can be moved voluntarily.
还有通常分布在鼻子下方的更短点、更硬点的触须 被成为“小触须”
But there are also shorter, stubbier whiskers, usually right under the nose, called microvibrissae.
很多动物都有两种触须 比如小鼠和大鼠
Many animals, like rats or mice, have both kinds.
那些动物用大触须测量空间
And in those creatures, it’s thought that the big ones are used for spatial tasks,
更偏向于用小触须来识别一些物体
while the little ones are more important for recognizing certain objects.
想象一下 你和大鼠一样能使用大触须你就能获取一些相当重要的信息
If you can move your big whiskers, like a rat does, you can actually get lots of really
比如空间信息 就像是用触须“看”到这些空间
valuable information about the space around you … almost like seeing, but with your hair.
这一行为有一个比较合适的名称“触须丈量”
This behavior actually has a name—aptly enough, it’s called whisking.
比如说 一只大鼠进入一个陌生的环境它将缓慢地移动 反复地抖动触须
For example, if a rat is new to an area, it will move slowly, flicking its whiskers back
以便触须能扫过大片区域 从而能更好地掌握周边的环境
and forth, letting them sweep over a broad area to get a good sense of the surroundings.
但如果它进入了一个熟悉的环境它将会快速地爬动 用触须丈量较小的区域
But if a rat already knows the space, it will move more quickly, and whisk over a smaller
确保自己不会碰壁
area just to make sure it doesn’t run into anything.
如果这只大鼠对某个东西很感兴趣它将会加快丈量速度
And if a rodent is especially interested in something, it will increase the speed of its
更好地分辨出这个东西
whisking to get a higher resolution sense of what the thing is.
还有一些动物则借助触须干一些“穷凶极恶”的事情……
Other animals use their whiskers for more nefarious purposes…
就比如捕食猎物
at least, if you’re a prey animal.
比如 小臭鼬会使用触须搜寻、捕食
The tiny etruscan shrew, for example, uses its whiskers to find and capture insects nearly
与自己体型相当的昆虫 即使在黑暗的隧道里
as large as itself, even inside dark tunnels.
海豹也一样 它们会使用触须捕食 甚至可以凭借触须
Seals, too, use the tactile hairs to hunt, and have whiskers so sensitive that they can
觉察到鱼的呼吸
actually sense fish breathing.
生物学家把这归功于海豹毛囊的神经末梢
Biologists think that’s because seals have as much as ten times the number of nerve endings
其数量是陆栖动物的十倍
per whisker follicle that land animals have.
现在你该知道 触须是多么有用了吧
OK, so you get that whiskers are super-useful,
而且对某些动物而言 触须还增添了气势
and on the right animal, they can be downright dashing.
既然这么有用 为什么人类没有触须呢?
So in that case, why don’t we have them?
也许我们曾经长过
Well, we probably did at one point.
至少人类祖先长过
Or, at least, our ancestors did.
触须是早期哺乳动物进化的重要表现灵长类动物也不例外
Whiskers are thought to have been an important adaptation in early mammals, including primates.
然而距今80万年前 我们似乎丧失了
But then, around 800,000 years ago, we appear to have lost the bit of DNA
这类触须基因
that allows for true whiskers.
而我们的远房表亲—类人猿—依旧保持了这一特征
However, our distant cousins—the other great apes—still have it, and you can see their
你凑近看 就会看到它们的触须
whiskers if you look closely.
这些触须没有猫的触须那么长 那么显眼但是黑猩猩 大猩猩 红毛猩猩
They are not the big flashy whiskers your cat has, but chimps, gorillas, and orangutans
都长有小触须 分布在嘴巴、眉毛周围
all have microvibrissae all around their mouths and eyebrows.
有证据表明 现在依然有些人在上嘴唇有发育不全的胡子
There’s even evidence that some people today have vestigial muscles in their upper lips
(他们认为)是祖先的触须残留
that are leftover from when our primate ancestors had whiskers—
虽然没有得到科学界的一致认可
although, not all scientists are convinced about that.
不管怎么说 当今人类没有触须 依旧生活地很好
Either way, modern humans seem to have gotten along just fine without whiskers.
原来负责接收触须发送的信息的大脑区域
All that brain space that was dedicated to getting information from whiskers is now used
现在负责合成触感图 其中大量信息来自于我们的指尖
to map our sense of touch, with a big chunk going to our fingertips.
另外 因为我们有相当发达的视觉导航系统所以我们不需要通过触须
And we have pretty good visual systems for navigating, so we don’t have to feel our
感受我们的周边环境
way around with hairs.
所以 如果你想出门用触须感知周边 或拥有一对漂亮的“夜魔侠”版的触须
So, if you’re wishing you could go out for a nice whisking, or had a sweet set of whiskers
千万别有这些想法
that could make you into like a real-life Daredevil, take heart.
没有这些触须才造就了你造就了人类
Not having them is part of what makes you human.
但如果你想看我是如何玩转机械猫耳朵的话
But if you want to see me rocking some scientific cat ears,
请观看我们的访谈秀《和医生阿曼达·杜利的大脑探索之旅》
check out our Talk Show about the brain with Dr. Amanda Duley.
描述中就有观看链接
There’s a link in the description.
我可是凭借大脑控制它们的(机械猫耳朵)
I move them with my mind.

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视频概述

古人类有没有触须,这一问题在科学界也没能达成一致一意见。抛开人类,大部分哺乳动物是离不开触须的,它们通过触须测量、捕食等…

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收集自网络

翻译译者

Goahead

审核员

Ah~Qiu

视频来源

https://www.youtube.com/watch?v=FA0jrbixGXU

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