This is a familiar scene in many sci-fi films, but could humans ever actually hibernate in real life?

這是在科幻電影裡常見的場景，但人類真的可以在現實生活中冬眠嗎？

Researchers interested in this question turned to the animal kingdom, where hibernation is commonplace, occurring in over 200 species that we know of.

對這個問題感興趣的科學家轉而研究普遍都會冬眠的動物界，我們已知約有兩百種物種會冬眠。

Take the Arctic ground squirrel.

以北極地松鼠為例。

Native to the North American tundra and northern Russia, this animal burrows beneath the permafrost and slips into a state of suspended animation.

牠們是北美凍原和北俄原生種，這種動物會挖地洞到永凍層之下潛伏，陷入假死狀態。

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

牠們的體溫驟然下降至攝氏 -2.9 度。

Others, like the female black bear, can multitask, giving birth and lactating while they're hibernating through the winter.

如母黑熊等其他動物可以同時進行多種任務：在冬眠時產子並哺乳。

The fat-tailed dwarf lemur prepares for its long dormancy by gorging on food and storing the majority of its fat reserves in its tail, doubling its body weight.

粗尾侏儒狐猴準備冬眠的方式是狂吃東西，並將大多脂肪儲存在尾巴裡，讓自己的重量多一倍。

After hibernation, it emerges looking as svelte as ever.

冬眠之後，牠們的尾巴又會變回細長的樣子。

So why do these animals go to such extremes?

為什麼這些動物會採取如此極端的行為？

Hibernation is a necessity, a survival tactic for making it through the harsh winter months when dwindling food and water reserves threaten survival.

對牠們而言，冬眠是必要的； 冬眠是一種求生技能，好讓自己度過長達數月的嚴冬，因為當糧食減少、受限，性命就會受到威脅。

For many years, experts believed hibernation happened only in arctic and temperate environments.

許多年來，專家相信冬眠只會出現在北極和溫帶地區。

But more recently, they've discovered animals hibernating even in arid deserts and tropical rainforests.

但最近他們發現，動物也會在乾燥的沙漠和熱帶雨林裡冬眠。

As hibernation kicks in, animals' heartbeats usually slow to about 1% to 3% of their original speed.

動物一開始冬眠，心跳通常就會減緩至原來的 1% 到 3%。

Like the dwarf lemur's, which drops from its usual roughly 180 beats per minute to just around 4.

像是侏儒狐猴，原本心跳每分鐘約 180 下，冬眠時會減至每分鐘四下。

Breathing also declines dramatically to just one breath every 10 to 21 minutes in the lemur's case.

牠們的呼吸也會大幅減少；以狐猴為例，牠們每 10 到 21 分鐘呼吸一次就好。

And black bears, like most hibernators, don't urinate or defecate the entire hibernation season.

黑熊跟大部分的冬眠動物一樣，整個冬眠期都不排尿或排遺。

Hibernating animals appear to stay alive by having just enough blood and oxygen moving around their bodies.

冬眠動物要維持生命，只需仰賴足夠的血液和氧氣在體內流動。

And scans of hibernating animals reveal that their brain activity has just about flatlined.

掃描冬眠動物後發現，牠們的腦部活動幾乎是靜止不動。

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

但冬眠並非漫長的冬日午覺。

As far as researchers know, in lemurs and ground squirrels anyways, the animals aren't even sleeping for most of it.

就研究人員所知，至少就狐猴和地松鼠而論，牠們大部分的冬眠時間幾乎都沒睡。

Hibernation is actually made up of regular bouts of reduced metabolic rate and body temperature known as torpor.

冬眠其實是由間歇性的降低代謝率和體溫組成，此現象稱為蟄伏。

Animals can be in torpor for a few days to 5 weeks, after which they resume normal metabolic rate and body temperature for about 24 hours, before going back into torpor again.

動物蟄伏的時間可長達五天到五個星期之久，之後的 24 小時牠們會恢復正常的代謝率和體溫，然後再次進入蟄伏狀態。

The phenomenon is known as an interbout arousal, and why it occurs is still a mystery.

這種現象稱為短暫覺醒期，它的成因仍是個謎。

The behaviors inherent in hibernation, like going 5 weeks without sleep or dropping to near-freezing body temperatures, would be potentially fatal to non-hibernating species like us.

冬眠時的行為，像是五週不睡覺、或體溫降至冰點，對我們這種不冬眠的物種來說可能會致命。

To find out how hibernators are able to do this, researchers turned their attention to those animals' genomes.

研究員為了找出動物為何能冬眠，將焦點轉向那些動物的基因組。

So far, they've discovered that hibernation is controlled by genes that turn off and on in unique patterns throughout the year, fine-tuning the hibernator's physiology and behavior.

到目前為止，他們發現冬眠是受基因控制：該基因整年會以一種獨特的排列形式關閉和啟動，並微調冬眠動物的生理機能和行為。

For example, ground squirrel, bear, and dwarf lemur studies have revealed that these animals are able to turn on the genes that control fat metabolism precisely when they need to use their fat stores as fuel to survive long periods of fasting.

例如松鼠、熊和侏儒狐猴的研究顯示：這些動物能夠精準地啟動牠們體內控制脂肪代謝的基因，並在需要運用儲存的脂肪做為燃料時，讓牠們度過漫長的禁食期。

And the genes in question are present in all mammals, which means that researchers could study hibernating mammals to see how their unique control of physiology might help humans.

這個基因在所有哺乳動物體內皆存在，意味著研究員可以透過冬眠的哺乳動物，研究牠們獨特的生理機能控制是否能幫助人類。

Understanding how hibernators deal with reduced blood flow could lead to better treatments for protecting the brain during a stroke.

了解冬眠動物如何應付血流減緩，也許能進一步幫助人類治療中風以保護腦部。

Figuring out how these animals avoid muscle deterioration might improve the lives of bedridden patients.

理解這些動物如何避免肌肉退化，或許能幫助那些長期臥病在床的患者，改善他們的生活。

And studying how hibernating animals control their weight with ease could illuminate the relationship between metabolism and weight gain in humans.

研究冬眠動物如何輕鬆控制體重，也許就能幫助我們了解人體新陳代謝和體重增加的關聯。

And yes, more research in this area might someday make human hibernation a real possibility.

當然，此領域的相關研究越多，或許某一天人類也有可能冬眠。

Imagine our surprise if the key to intergalactic travel turns out to be ground squirrels, black bears, and dwarf lemurs.

想像我們會有多訝異，發現銀河之旅的關鍵居然是地松鼠、黑熊和侏儒狐猴。