How does hibernation work? - Sheena Lee Faherty

翻译人员: Zijian Xiao 校对人员: Junnan Li

Onboard the spacecraft, the astronauts preset the timer,

在宇宙飞船上， 宇航员通过预调时间装置，

enclose themselves in capsules,

把他们封进密闭的胶囊中，

and fall into a deep hibernation

进入深度的休眠状态，

that’ll carry them several hundred years into the future.

然后穿梭数百年的时光到达未来。

This is a familiar scene in many sci-fi films,

这是许多科幻电影中常见的桥段，

but could humans ever actually hibernate in real life?

但是人类在现实生活中 真的能休眠吗？

Researchers interested in this question turn to the animal kingdom,

科学家们对这个问题饶有兴趣。 对于动物们来说，

where hibernation is commonplace,

休眠是再正常不过的了，

occurring in over 200 species that we know of.

光是我们知道的休眠的物种 就超过 200 种。

Take the Arctic ground squirrel.

拿北美苔原地区本土的北极地鼠，

Native to the North American tundra and northern Russia,

和俄罗斯北部的北极地鼠举例，

this animal burrows beneath the permafrost

这种生物会在冻土层下面挖洞，

and slips into a state of suspended animation,

然后迅速进入暂停活动的状态，

its body temperature plummeting to a frigid -2.9 degrees Celsius.

它们的体温会迅速 下降至零下 2.9 摄氏度。

Others, like the female black bear, can multitask,

此外，像雌黑熊在冬眠时 还能进行其他生理活动，

giving birth and lactating while they’re hibernating through the winter.

比如分娩和哺乳，

The fat-tailed dwarf lemur prepares for its long dormancy

肥尾鼠狐猴则是靠摄取大量食物，

by gorging on food and storing the majority of its fat reserves in its tail,

和它们尾巴中储存的相当于 身体重量的大量脂肪

doubling its body weight.

来度过冬眠的，

After hibernation, it emerges looking as svelte as ever.

冬眠结束后， 它们看起来又像平时一样瘦小。

So why do these animals go to such extremes?

那么，为何这些动物会这样做呢？

Hibernation is a necessity,

因为休眠对它们来说太重要了，

a survival tactic for making it through the harsh winter months

这是确保它们能够度过 严寒数月的一种生存策略，

when dwindling food and water reserves threaten survival.

冬季里稀缺的食物 和水会威胁它们的生存。

For many years, experts believed hibernation happened

多年来，专家们认为，

only in arctic and temperate environments.

动物的休眠只会发生 极地和温带地区。

But more recently, they’ve discovered animals hibernating

但近年来，科学家们发现，

even in arid deserts and tropical rainforests.

动物甚至在干旱的沙漠中 和热带雨林也会进行休眠。

As hibernation kicks in,

一旦动物进入休眠状态，

animals’ heartbeats usually slow to about 1 to 3% of their original speed,

它们的心率会下降至 正常速率的 1% 至 3%。

like the dwarf lemur’s,

拿鼠狐猴的心跳来说，

which drops from its usual roughly 180 beats per minute

心跳会从每分钟约 180 次，

to just around four.

下降到约每分钟 4 次。

Breathing also declines dramatically

呼吸活动也显著降低，

to just one breath every 10 to 21 minutes in the lemur’s case.

对狐鼠来说甚至每 10-21 分钟 只需要呼吸一次。

And black bears, like most hibernators,

而黑熊，还有大多数休眠动物，

don’t urinate or defecate the entire hibernation season.

整个休眠期都不需要排尿和排便。

Hibernating animals appear to stay alive

当有足够的血和氧在身体内循环时，

by having just enough blood and oxygen moving around their bodies.

休眠的动物会重新苏醒过来。

And scans of hibernating animals reveal that their brain activity

通过对休眠动物进行扫描显示，

has just about flat-lined.

它们的大脑活动比较平缓。

But hibernation isn’t a long winter’s nap.

但是休眠并不像冬眠那样，

As far as researchers know,

就研究者所知，

in lemurs and ground squirrels anyway,

至少对狐鼠和地松鼠来说是这样的。

the animals aren’t even sleeping for most of it.

对大多数动物来说甚至并没有睡着，

Hibernation is actually made up of regular bouts of reduced metabolic rate

休眠实际上是为了补偿 经常性出现的新陈代谢率降低，

and body temperature known as torpor.

和体温降低引起的倦怠感。

Animals can be in torpor for a few days to five weeks,

动物们这种非活跃状态 甚至可能经历数天到五周。

after which they resume normal metabolic rate and body temperature

在这之后，它们又会恢复到 正常的新陈代谢率和体温，

for about 24 hours,

直到下一次倦怠期来袭，

before going back into torpor again.

中间大约间隔 24 小时。

The phenomenon is known as an interbout arousal,

这种现象被称为阵间觉醒。

and why it occurs is still a mystery.

至于为什么会出现这种现象， 目前仍然是个谜。

The behaviors inherent in hibernation,

休眠期中出现的 一些固定的生理行为，

like going five weeks without sleep,

比如持续五周左右不睡觉，

or dropping to near-freezing body temperatures

或者体温骤降等，

would be potentially fatal to non-hibernating species like us.

对于我们这些没有休眠行为 的物种来说可能有潜在的致命威胁。

To find out how hibernators are able to do this,

为了查明休眠动物是如何做到的，

researchers turned their attention to those animal’s genomes.

研究者们把注意力转向了 这些动物的基因组。

So far, they’ve discovered that hibernation is controlled by genes

到目前为止，他们已经发现， 贯穿全年的休眠活动的开始和结束，

that turn off and on in unique patterns throughout the year,

都受到独特的基因模式的控制，

fine-tuning the hibernator’s physiology and behavior.

基因组能完美协调休眠动物 的生理活动和行为。

For example, ground squirrel, bear and dwarf lemur studies

举个例子，对地松鼠， 熊和鼠狐猴的研究表明，

have revealed that these animals are able to turn on the genes

当这些动物需要消耗储存的脂肪时， 这些动物可以调动基因

that control fat metabolism

来精准控制脂肪代谢，

precisely when they need to use their fat stores

储存的脂肪如同燃料，

as fuel to survive long periods of fasting.

来支持长时间的断食。

And the genes in question are present in all mammals,

我们所讨论的这种基因， 在所有哺乳动物体内都有。

which means that researchers could study hibernating mammals

这意味着研究者可以 通过研究休眠的哺乳动物，

to see how their unique control of physiology might help humans.

来查明它们对生理上的 独特控制如何尽可能造福人类。

Understanding how hibernators deal with reduced blood flow

了解休眠是如何减缓血液流动的，

could lead to better treatments for protecting the brain during a stroke.

有可能改善大脑在中风时的治疗。

Figuring out how these animals avoid muscle deterioration

弄清楚这些动物 是如何防止肌肉退化的，

might improve the lives of bedridden patients.

也许可以提高卧床不起 的病患的生存率。

And studying how hibernating animals control their weight with ease

研究休眠动物如何通过 放松来控制它们的体重，

could illuminate the relationship between metabolism and weight gain in humans.

可以用来解析人体新陈代谢 和体重增长之间的关联。

And yes, more research in this area

是的，这个领域的研究越多，

might someday make human hibernation a real possibility.

也许有天能实现让人类进行休眠。

Imagine our surprise if the key to intergalactic travel

设想一下，实现人类 星际旅行的关键线索就藏在

turns out to be ground squirrels, black bears, and dwarf lemurs.

地松鼠、黑熊和鼠狐猴身上， 简直太令人惊奇了！