Vampires. They're in all kinds of spooky stories — and certain Young Adult fantasy romance novels.
吸血鬼 他们出现在各种惊悚故事中 以及某些青少年奇幻言情小说中
There may not be undead, blood-sucking humans walking around.
世界上可能不存在四处游走的不死吸血鬼
But blood-drinking mammals do exist, in the form of vampire bats.
但是吸血的哺乳动物确实存在 那就是吸血蝙蝠
Surviving on a diet of only blood, also known as hematophagy, isn't easy,
生存饮食唯有血 又称吸血鬼 它们生活却不易
and vampire bats are one of the few mammals that have evolved a thirst for blood.
吸血蝙蝠是少数几种进化出对血液有渴望的哺乳动物
Along the way, they also developed some useful techniques to help them survive.
在这过程中 它们发展出一些有用的技能来帮助它们生存
To be clear, vampire bats don't exactly suck blood.
要知道的是 吸血蝙蝠并没有真正地吸血
Instead, they drink blood using the physics of capillary action,
相反 它们通过毛细血管活动的物理特性来吸食血液
where a liquid can move through a narrow tube or cylindrical space — often against the downward force of gravity.
在毛细血管中液体可以通过狭窄的管道或者是圆柱形的空间(一般与重力的向下的力量相对) 移动
Vampire bats have special grooves on their tongues —
吸血蝙蝠在其舌头上有着独特的凹槽
which, along with their lower lip and incisors, can create a tube-like shape that easily wicks up the liquid.
这些凹槽在它们嘴唇和门齿的下方 能够轻易地依靠毛细作用使液体通过类管形
They do make a lapping motion with their tongue, which helps speed up the process,
它们会用舌头做出舔的动作 这样能够帮助它们加快进食进程
but it isn't necessary for capillary action to work.
但是这对毛细血管活动作用是不必要的
Another thing that helps keep the blood flowing is the bats' saliva.
另一方面 蝙蝠的唾液也有助于保持血液的流动
Vampire bat saliva contains a protein called desmoteplase, which researchers nicknamed Draculin.
吸血蝙蝠的唾液包含着一种蛋白质 叫做去氨普酶 研究人员给其取绰号叫德拉库拉吸血鬼之王
It acts as an anticoagulant to stop blood from clotting.
这是一种抗凝剂 能够防止血液凝结
Researchers have actually isolated this protein from vampire bat saliva
研究人员实际上已经从吸血蝙蝠唾液中分离出了这种蛋白质
in the hopes of turning it into an anti-stroke medication since it helps stop blood from clotting,
并希望把这种物质加入抗中风药物里 因为它能够帮助血液凝固
it might also be good at preventing blood clots in human brains.
它同样也能很好的阻止人类大脑血液的凝固
So when a vampire bat bites into a juicy blood vessel,
因此 当吸血蝙蝠咬入多汁的血管时
the proteins in the saliva keep the animal's blood free-flowing for a big meal.
唾液中的这种蛋白质会使动物的血液自由流动 成为一顿大餐
And vampire bats need a big meal every time they feed. Blood isn't a very rich food source.
吸血蝙蝠每次吸食都需要一顿大餐 血液不是很丰富的食物来源
It's mostly made up of water, with small amounts of protein, sugar, and trace minerals. It's completely lacking in fat.
它主要由水构成和少量蛋白质、糖类和微量元素 而且完全缺乏脂肪
And animals tend to need fat, which is a major type of energy storage in a balanced diet.
动物往往需要脂肪 那可是主要类型能量中的储备饮食
So vampire bats need to drink about half their weight in blood every day to get enough nutrients
因此吸血蝙蝠必须摄取占自身体重一半的血液 才能获得足够的营养
to keep their metabolism running smoothly.
这能够保持它们的新陈代谢正常进行
Since that means they're taking in a lot of water, their digestive and excretory systems
当它们摄取了大量的水 它们消化和排泄的系统就会很快地滤出水
quickly filter out water and leave the proteins, sugars, and minerals to be digested.
筛选并留下蛋白质、糖类和微量元素
In fact, vampire bats will often start urinating even before they've finished feeding, just to keep things flowing.
事实上 吸血蝙蝠在开始进食前经常会开始撒尿 只是为了保持物质的流动
Finding food takes some special skills, though.
不过寻找食物需要一些特别的技巧
Like other bats, vampires use echolocation to fly around and look for prey.
像其他的蝙蝠一样 吸血蝙蝠也使用回声定位能力来飞行和捕食
They also have a keen sense of smell and decent eyesight.
它们同样有着敏锐的嗅觉和相当好的视力
But the wrinkly faces of vampire bats have specialized nerve fibers loaded with proteins
但是吸血蝙蝠皱巴巴的脸上有着专门的神经纤维附着蛋白质
that allow them to detect the infrared radiation given off by warm-blooded animals.
这些蛋白质使它们发现有着热量动物发射的红外线的辐射
Once they find something to eat, the three known species of vampire bats all have unique feeding behaviors.
一旦发现可以吃的食物 吸血蝙蝠 这个众所周知的特别物种全都会有独特的 饮食习惯

Common vampire bats feed only on blood from mammals, and they prefer livestock.
普通的吸血蝙蝠只吃哺乳动物的血液 但是它们更喜欢家畜的
So these bats evolved ways to quickly maneuver on the ground and reach their prey more easily.
所以这些蝙蝠进化成可以使用计策
They have strong hind leg muscles and elongated thumbs at the tips of their wings, which they use to jump around.
它们在它们翅膀两边拥有强壮的后脚肌肉和细长的拇指 它们用来到处蹦哒
They're agile enough to escape from ground predators.
它们足够的敏捷来逃避地面的捕食者
Hairy-legged vampire bats, on the other hand, feed exclusively on bird blood and hunt from the tree tops.
腿上毛茸茸的吸血蝙蝠 另一方面 专门以鸟类的血为食并且从树顶捕食
They jump onto unsuspecting birds from above, and usually try to bite the bird in the cloaca--
它们从上面跳到毫无防备的某只鸟身上经常尝试着在阴沟里咬死这只鸟
the multipurpose exit point for a bird's digestive and urinary tracts,
对于一只鸟的消化和泌尿系统的多目标出口点
and also the place where it keeps its reproductive organs.
这也是它保持它生殖器官的地方
For some reason, the birds tend not to like this very much.
因为某些原因 鸟儿好像并不是十分喜欢这个
So, to stop the bird from fighting back or knocking it off,
所以为了阻止鸟儿反攻或者撞掉它
the hairy-legged vampire bat uses the big bony spurs on its ankles to help it hang upside-down and latch onto its prey.
这种毛腿吸血蝙蝠用在脚踝上大大的瘦骨嶙峋的刺去帮助它倒挂着并且抓住 它的猎物
White-winged vampire bats feed on both mammals and birds, but they evolved a few tricks to help them feed on chickens.
白翼吸血蝙蝠以哺乳动物和鸟类为食 但是它们发明了一些技巧去帮助它们以鸡为食
Sometimes, the bat lands on the chicken's back, so the chicken thinks the bat is really a mounting rooster.
有时候 这种蝙蝠落在鸡背上 所以鸡以为蝙蝠是正在爬到它背上的公鸡
So the chicken just crouches down, giving the bat access to its neck for feeding.
所以鸡仅仅低下头 给了蝙蝠一个在它（鸡）脖子上捕食的机会
Other times, the white-winged vampire sneaks up from underneath the chicken
别的时间 这种白翼吸血蝙蝠从鸡的下面溜走
and nuzzles against the brood patch -- a featherless spot of skin normally used to keep chicks warm.
并且用鼻子挨在鸡孵化小鸡的地方(鸡皮肤上平常用来使小鸡保持温暖的没有毛的一块区域)
The chicken thinks it's being nuzzled by a baby chick, and lets the vampire latch on and start drinking blood.
鸡认为这里被一只小鸡用鼻子挨着 让吸血蝙蝠站在上面然后吸血蝙蝠开始吸血
With all these complicated feeding techniques, you'd think vampire bats would have no trouble finding a meal.
吸血蝙蝠拥有这么多复杂的捕食技巧 所以你可能会认为它在寻找食物时所向无敌
But sometimes they don't get enough.
但是其实不是这样
Luckily for the bats that don't find enough food, vampire bats live in large colonies that can contain thousands of bats,
幸运的是 吸血蝙蝠住在很大的殖民地里 这里容下成千只蝙蝠
and they take care of each other using a behavior called reciprocal altruism.
对于那些没有捕获足够食物的蝙蝠来说 它们相互照顾 互助互利
Often, one bat will sacrifice their own needs for another,
经常地 一只蝙蝠会为了另外一只而牺牲它们自己的需求
with the assumption that they'll be helped in return in the future.
带有它们在将来会被帮助作为回报的假设
The main way they do this is very appetizing: they regurgitate blood to share with bats that weren't able to get a meal.
它们这样做的方式也很开胃 它们将血回流给那些不能捕食的蝙蝠
Bats who've shared blood meals in the past get larger donated meals in return, compared to more selfish bats.
在过去 和那些自私的蝙蝠比起来 一起分享过血食的蝙蝠会得到更多的捐赠 作为食物的回报
So yes: like Dracula, vampire bats are skilled, blood-drinking hunters.
所以确实如此 像吸血鬼一样 吸血蝙蝠是经验丰富的饮血捕食者
But they also have to be extra nice to each other to help their colony survive.
但是它们为了帮助它们的领土服务也必须对别人要很好
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感谢收看今天科学秀的由我们的老顾客patreon带给大家的小故事
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如果你想帮助支持这个视频，马上去点击patreon.com/scishow.
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不要忘记去youtube.com/scishow去订阅哦！