The World‘s Highest-Dwelling Mammal Lives atop a Volcano
世界住在最高海拔的哺乳動物生活在火山上
In 2013 two mountaineers reached the top of Volcán Llullaillaco， a 22，000-foot-tall volcano on the border of Chile and Argentina—when they saw something unexpected。 Just 2，000 feet below the summit， the climbers spotted a mouse scurrying across the snow。
在2013年兩名登山者登上了火山Llullaillaco的山頂，它是一座22000英尺高坐落於智利和阿根廷的邊界的火山，他們看到了某些意想之外的事情。在頂峰的2000英尺下，登山者發現一隻老鼠在雪地上疾跑。
“It’s really a remarkable sighting， because no one expected wild mammals to be living at an elevation of over 20，000 feet。 At that elevation， the scarcity of oxygen makes it really a challenging place to survive and function。 But also， the extreme cold。 It’s an extremely inhospitable environment。”
“這是一個值得注意的現象，原因是沒有人會想到野生哺乳動物會居住在超過20000英尺高的地方。在這高度下，稀薄的氧氣讓生存和運轉成為一種挑戰。除此之外，這裡極度寒冷。這是一個極其不適宜居住的環境。”
Jay Storz， an evolutionary biologist at the University of ［Nebraska–Lincoln］。 The climbers reached out to Storz because he studies how animals adapt to high altitudes。 And he was so intrigued that he decided to make his own trip to survey the area。
Jay Storz是 ［Nebraska–Lincoln］大學的一位進化生物學家。登山者們跑去這座火山，是因為他研究動物是如何適應高海拔地區的。他非常感興趣，他決定獨自調查這一區域。
Storz and his colleagues spent a month at Llullaillaco earlier this year， where they confirmed what the climbers saw。 They found mice everywhere， including on the summit—officially setting a new record for the world’s highest-dwelling mammal。
Storz和他的同事在今年早些時候花了一個月的時間在火山上，他們確認登山者們看到的一切。他們發現到處是老鼠包活山頂，老鼠創下了一項關於世界居住最高的哺乳動物的記錄。
Storz says the summit sighting was fortuitous。 His climber partner， Mario Pérez Mamani， saw the mouse dive under a rock just as Storz made it to the top， exhausted and groggy from the thin air。 It took Storz a minute to gather his wits， but he eventually managed to catch the mouse with his hands。 Storz collected that mouse and others as museum specimens that will enable future scientific analysis。
Storz說到頂峰的景象很意外。他的登山同伴——Mario Pérez Mamani，看到，當Storz從稀薄的空氣中登上山頂時，看到老鼠從岩石下面潛入水中。這花了一分鐘讓Storz回過神來，但是他最終用手抓住老鼠。Storz收集的老鼠和其他老鼠作為博物館標本，用於未來科學分析。
They also recorded their encounter on video。 The report is in the
Proceedings of the National Academy of Sciences
。
這一紀錄在影片中。報告發布在《國家科學院院刊》上。
Now that he’s home， Storz wants to understand how these mice can survive in such harsh conditions and， conversely， what prevents other animals from venturing so high。
現在他在家裡，Storz想明白這些老鼠如何在惡虐的環境下生存，相反是什麼不可以讓動物在高處生存。
“Clearly， the mice that are living at these extreme altitudes have physiological capacities that are very different from your typical rodent。”
“顯然，居住在這些海拔地區的老鼠有與典型的齧齒類動物有很大不同的生理能力。”
He and his colleagues are comparing the genomes of the mice from Llullaillaco to their lowland relatives to see if they can identify the animal’s high-altitude adaptations。 And he’s curious whether they have evolved some of the same strategies as mice that live at high elevations in North America and the Himalayas。
他和他的同事比較了火山上的和低海拔地區的老鼠的基因組，看看可不可以辨認出適應高海拔的能力。他感興趣的是它們是否有進化出和生活在北美和喜馬拉雅高海拔地區的老鼠的特徵。
Storz also wants to know how mice are finding food on top of a barren， rocky volcano， thousands of feet above the highest green plants。 On his next trip， he plans to analyze the stomach contents of the animals they capture。
Storz還想知道老鼠是如何在距最高的綠色植物幾千英尺的貧瘠岩石火山上找到食物的。在他下一次旅行中，他打算分析它捕獲的老鼠的胃中的食物。
“It’s really an open question whether most species—whether their elevational limit is set by physiological tolerance or just the lack of ecological opportunity。 It’s probably a combination of both。”
“這的確是一個開放的問題，是否大部分動物的海拔極限是由生理上的限制或者生態機會的缺乏來決定的，或許兩者兼有。”
Whatever the answer， Storz suspects there may be more high-altitude animals out there than scientists thought。 It’s just a matter of climbing high enough to find them。
無論答案是什麼，Storz猜測在高海拔生活的動物要比我們想象中的多。這需要爬的足夠高來找到它們。