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

そして数百年先の未来へと至る深い冬眠に入ります。

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

これは多くのSF映画でおなじみのシーンですが、人間が実際に冬眠することはあるのでしょうか？

Take the Arctic ground squirrel.

この疑問に興味を持った研究者達は動物界に目を向けました。そこでは冬眠は何ら特別ではなく、

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

知っているだけで 200 を超える種で行われています。

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

ホッキョクジリスを例にあげましょう。

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

北アメリカのツンドラやロシア北部を原産とした、

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.

この動物は永久凍土の下に潜り込み、活動停止した状態になります。

After hibernation, it emerges looking as svelte as ever.

体温は非常に冷たい -2.9 度にまで急降下します。

So why do these animals go to such extremes?

メスのツキノワグマなど、マルチタスクを行うことができる動物もいます。

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

冬眠中に出産しながら授乳もするのです。

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

フトオコビトキツネザルは、食べ物をがつがつ食べて長い休眠に備えます。

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

脂肪の大部分をしっぽにたくわえ、体重は 2 倍になります。

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

冬眠の後、見た目は変わらずしなやかです。

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

では、なぜこれらの動物はそれほどに極端なことをするのでしょうか？

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

冬眠は必要なものです、

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

減っていく食糧と水源が生存を脅かす厳しい冬の数か月間を乗り切るための生存術なのです。

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

長年、専門家達は冬眠は北極圏と温暖な環境でのみ行われると考えていました。

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

しかし、最近では、乾燥した砂漠や熱帯雨林でも冬眠する動物が見つかりました。

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

冬眠が始まると、動物の心拍数は通常、元の速度の約 1 %から 3 %へと遅くなります。

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

コビトキツネザルのように、通常は毎分約 180 回の心拍から約 4 回に低下します。

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

キツネザルの場合は、呼吸も劇的に減少し、 10 ～ 21 分ごとに 1 回の呼吸になります。

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.

また、ツキノワグマは、ほとんどの冬眠動物と同様に、冬眠期間を通して排尿や排便をしません。

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

冬眠中の動物は、十分な量の血液と酸素が体内を循環することで生きているようです。

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.

また、冬眠中の動物をスキャンすると、脳の活動がほぼ停止していることがわかります。

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

しかし、冬眠は冬の長い昼寝ではありません。

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.

研究者の知る限り、とにかくキツネザルとリスの中でも、

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.

動物達はほとんどの期間は眠ってさえいません。

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.

冬眠は、実際には休止状態と呼ばれる、代謝率や体温が低下する定期的な期間で成り立っています。

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

動物は数日から5週間、休止状態になることができ、

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

その後、通常の代謝率と体温を約 24 時間再開し、その後再び休止状態に戻ります。

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

この現象は「覚醒」として知られており、なぜそれが起こるのかはまだ謎です。

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

冬眠に固有の行動、たとえば 5 週間も寝ないでいたり、

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

体温が氷点下の温度にまでさがったりするなどは私達のような冬眠をしない種にとっては致命的となる場合があります。