馴鹿的時間不一樣(雙語有聲)
作者：melodyfangta
來源：滬江論壇
2010-04-01 10:37
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詼諧的語言，生動的內(nèi)容一分鐘快速掌握科技最新動態(tài)
How Its Internal Clock Is Read, Knows Reindeer
Humans are pegged to a 24-hour cycle. We're locked into it not just by day and night—there's the master timepiece in the brain called the circadian clock. But it doesn't make sense to live by a 24-hour clock in the Arctic, where it's dark or light for months at time. The solution? Lose the daily clock. Which is exactly what reindeer seem to have done, according to a study in Current Biology.
人類被限制在24小時的循環(huán)內(nèi)，不僅僅是被日夜限制其中，大腦中還有一種叫晝夜節(jié)律鐘的計時器約束著我們?？稍跁円篂楹脦讉€月的北極圈里，按照24小時來起居就沒什么意義了。有什么解決辦法嗎？有，就是拋棄白天的鐘。據(jù)《當(dāng)代生物學(xué)》的一篇研究看來，馴鹿就是一直這么做的。
Reindeer don't sleep eight hours like we do, and there's no obvious 24-hour pattern to their lives. They just chomp on tundra, nap a few hours and feast again. But they still need to know when to mate, pack on fat or thicken their coats. So they probably rely on an annual clock instead, set by the hormone melatonin.
馴鹿不像我們要睡足八小時，起居活動也沒有明顯的24小時規(guī)律。它們只是在苔原上大嚼特嚼，睡上幾小時，接著再吃。即使如此它們也還是得了解何時交配、儲存脂肪或是增加皮毛，因此它們依賴的可能是由荷爾蒙褪黑素調(diào)節(jié)的年鐘。
In humans melatonin levels rise at night, in response to darkness and cues from the circadian clock. In reindeer, even if they're missing a circadian clock, melatonin levels still spike when it's dark and drop when it's light, making the equinoxes an ideal time to synchronize their annual clocks.
拿人體來說，由于對黑暗作出反應(yīng)并受晝夜節(jié)律鐘的影響，褪黑素值會在晚上升高。即使缺少晝夜節(jié)律鐘，馴鹿的褪黑素值仍會在黑暗時達(dá)到頂峰，光亮?xí)r就下降，使晝夜平分點成為它們調(diào)節(jié)年鐘的最佳時期。
So ask a reindeer what time of year it is, and it may be able to give you the date. Just don't be offended if it won't give you the time of day.
所以，要問馴鹿這是一年中的什么時段，它可能會給你個準(zhǔn)確的日期，可如果它答不上來現(xiàn)在幾點的話你就別生氣了。
