考拉的“樹干空調(diào)”

陳延洲

by Michael Slezak

樹袋熊，又稱“考拉”，是澳大利亞的國(guó)寶，性情溫順，體態(tài)憨厚，以桉樹葉和嫩枝為食；一生的大部分時(shí)間都生活在桉樹上，但偶爾也會(huì)因?yàn)楦鼡Q棲息樹木或吞食幫助消化的礫石下到地面?？祭眢w新陳代謝較慢，每日需睡眠17到20小時(shí)。

Koalas spend a lot of their time sleeping， clinging to1 tree branches. But far from being lazy， it seems tree-hugging is an efficient way to keep cool.

考拉大多數(shù)時(shí)間都會(huì)抱住樹枝睡覺。但也許這并不是因?yàn)樗鼈儜卸?，而是因?yàn)楸е鴺淇梢杂行У厥棺约罕３譀鏊?/p>

Koalas can usually endure2 temperatures above 40℃. They cool themselves by panting3 and licking their fur， but they do not sweat. So Natalie Briscoe from the University of Melbourne in Australia expected them to move into shadier areas when the temperature rose. But， in fact， they stay in shady areas most of the time anyway.

考拉一般可以忍受40多攝氏度的高溫。它們通過(guò)喘息和舔舐自己的皮毛來(lái)降溫，但是它們不會(huì)出汗。于是澳大利亞墨爾本大學(xué)的納塔利·布里斯柯認(rèn)為它們?cè)跉鉁厣邥r(shí)會(huì)躲到陰涼地兒去。不過(guò)，實(shí)際上它們大部分時(shí)間都是在陰涼地兒呆著。

“As it got hotter， they started moving down to the tree trunks and hugged really tightly4 to the trunks.” says her colleague Michael Kearney.

“當(dāng)天氣熱起來(lái)的時(shí)候，它們會(huì)往下轉(zhuǎn)移到樹干，然后緊緊抱住它?！彼耐逻~克爾·卡尼這樣說(shuō)。

So Briscoe used infrared cameras to measure5 the temperatures of the trunks and found they were much cooler than the air on hot days. At that point， “it was absolutely6 obvious what they were doing，” says Kearney.

布里斯柯用紅外照相機(jī)測(cè)量了樹干的溫度后發(fā)現(xiàn)，樹干的確在天熱時(shí)比空氣更涼爽。從這一點(diǎn)來(lái)看，“考拉抱樹的原因顯而易見了?！笨嵴f(shuō)道。

Briscoe tracked 37 koalas and watched their behaviour. He found that they not only moved to lower parts of the trunks in hot weather but also changed their posture， tending to hug branches when it was very warm， but sit upright7 in mild weather. In extremely hot conditions， they even spent time hugging the trunks of wattle trees， which they cant eat， but which have cooler trunks.

布里斯柯追蹤了37只考拉并觀察它們的行為，他發(fā)現(xiàn)它們不僅會(huì)在天熱時(shí)挪到樹干較低的位置，還會(huì)根據(jù)情況變換自己的姿勢(shì)，比如在很熱的時(shí)候抱住樹枝，而在溫和的天氣里筆直地坐著。在極度高溫的條件下，它們甚至?xí)ё〗鸷蠚g樹（考拉不吃金合歡樹的樹葉）——僅僅因?yàn)檫@種樹的樹干更涼爽。

The trees are probably cooled by the roots sucking up water from underground where the sun doesnt heat the soil so much， says Kearney.

卡尼說(shuō)，樹干涼爽的原因很可能是因?yàn)榈叵碌耐寥啦粫?huì)受到太陽(yáng)的炙烤，從而使樹根所吸收的地下水分可以保持清涼。

Kearney says other mammals often adapt8 their behaviour to keep cool， just as humans do. But this is the first time tree-hugging has been shown to be used this way. “It could be what leopards in Africa are doing too，” says Kearney.

卡尼說(shuō)，其它的哺乳動(dòng)物也和人類一樣，經(jīng)常會(huì)調(diào)整自己的行為來(lái)降溫。不過(guò)這次研究發(fā)現(xiàn)的通過(guò)抱樹來(lái)降溫還是前所未聞的?！胺侵薇坪跻苍谑褂眠@種方法?！笨栒f(shuō)道。

Koalas habitat is shrinking9 and their climate is warming. “Understanding what makes the trees a suitable10 habitat is essential for conservation11，” says Bill Ellis of the University of Queensland in Brisbane.

考拉的棲息地在慢慢減少，氣候也在逐漸變暖?！盀榱吮Ｗo(hù)考拉，我們必須了解樹的哪些特點(diǎn)可以使之成為適合考拉生存的棲息地?！辈祭锼拱嗬ナ刻m大學(xué)的比爾·埃利斯這樣說(shuō)。

[1] cling to 依靠；依附；緊握不放 [2] endure vt. 忍耐；容忍 [3] pant vi. 氣喘 喘息

[4] tightly adv. 緊緊地；堅(jiān)固地 [5] measure vt. 測(cè)量 [6] absolutely adv. 絕對(duì)地；完全地

[7] upright adj. 垂直的，直立的 [8] adapt vt. 使適應(yīng) [9] shrink vi. 減少；收縮

[10] suitable adj. 適當(dāng)?shù)?；相配?[11] conservation n. 保存；保護(hù)